diff --git a/backend/src/modules/auth/auth.controller.ts b/backend/src/modules/auth/auth.controller.ts
index 860aade..1e68517 100644
--- a/backend/src/modules/auth/auth.controller.ts
+++ b/backend/src/modules/auth/auth.controller.ts
@@ -126,7 +126,11 @@ export class AuthController {
   @ApiBearerAuth('JWT-auth')
   @ApiOperation({ summary: 'Create organization for current user' })
   async createOrganization(@Req() req, @Body() dto: CreateOrganizationDto) {
-    return this.authService.createOrganization(req.user.id, dto);
+    return this.authService.createOrganization(
+      req.user.id,
+      req.user.organizationId,
+      dto,
+    );
   }
 
   // =========================
diff --git a/backend/src/modules/auth/auth.service.ts b/backend/src/modules/auth/auth.service.ts
index 7e3a4a1..102e59c 100644
--- a/backend/src/modules/auth/auth.service.ts
+++ b/backend/src/modules/auth/auth.service.ts
@@ -4,6 +4,7 @@ import {
   UnauthorizedException,
   BadRequestException,
   ConflictException,
+  ForbiddenException,
   InternalServerErrorException
 } from '@nestjs/common';
 import { JwtService } from '@nestjs/jwt';
@@ -270,7 +271,11 @@ export class AuthService {
     return this.login({ email, password } as any, validatedUser);
   }
 
-  async createOrganization(userId: string, dto: CreateOrganizationDto) {
+  async createOrganization(
+    userId: string,
+    currentOrganizationId: string | undefined,
+    dto: CreateOrganizationDto,
+  ) {
     const owner = await this.prisma.user.findUnique({
       where: { id: userId },
       select: { id: true },
@@ -280,6 +285,28 @@ export class AuthService {
       throw new UnauthorizedException('User not found');
     }
 
+    if (!currentOrganizationId) {
+      throw new ForbiddenException(
+        'Select an organization before creating a new one.',
+      );
+    }
+
+    const currentMembership = await this.prisma.membership.findUnique({
+      where: {
+        userId_organizationId: {
+          userId,
+          organizationId: currentOrganizationId,
+        },
+      },
+      select: { isOwner: true },
+    });
+
+    if (!currentMembership?.isOwner) {
+      throw new ForbiddenException(
+        'Only owners of the current organization can create new organizations.',
+      );
+    }
+
     const organization = await this.prisma.$transaction(async (tx) => {
       const createdOrganization = await tx.organization.create({
         data: {
diff --git a/backend/src/modules/staff/staff.controller.ts b/backend/src/modules/staff/staff.controller.ts
index e4732ea..8183f32 100644
--- a/backend/src/modules/staff/staff.controller.ts
+++ b/backend/src/modules/staff/staff.controller.ts
@@ -80,6 +80,32 @@ export class StaffController {
     return this.staffService.updateMember(req.user.id, organizationId, membershipId, dto);
   }
 
+  @Patch('members/:membershipId/enable')
+  @UseGuards(JwtAuthGuard)
+  @ApiOperation({
+    summary: 'Re-enable a disabled staff member (uses one plan seat; no new invitation)',
+  })
+  enableMember(
+    @Req() req: { user: { id: string; organizationId?: string } },
+    @Param('membershipId') membershipId: string,
+  ) {
+    const organizationId = this.staffService.getOrganizationIdFromUser(req.user);
+    return this.staffService.enableMember(req.user.id, organizationId, membershipId);
+  }
+
+  @Patch('members/:membershipId/disable')
+  @UseGuards(JwtAuthGuard)
+  @ApiOperation({
+    summary: 'Disable staff member (frees a seat; member cannot access this organization)',
+  })
+  disableMember(
+    @Req() req: { user: { id: string; organizationId?: string } },
+    @Param('membershipId') membershipId: string,
+  ) {
+    const organizationId = this.staffService.getOrganizationIdFromUser(req.user);
+    return this.staffService.disableMember(req.user.id, organizationId, membershipId);
+  }
+
   @Delete('members/:membershipId')
   @UseGuards(JwtAuthGuard)
   @ApiOperation({ summary: 'Remove staff member from organization' })
diff --git a/backend/src/modules/staff/staff.service.ts b/backend/src/modules/staff/staff.service.ts
index 2dcd3b2..60f4b23 100644
--- a/backend/src/modules/staff/staff.service.ts
+++ b/backend/src/modules/staff/staff.service.ts
@@ -7,6 +7,7 @@ import {
 } from '@nestjs/common';
 import * as bcrypt from 'bcrypt';
 import { createHash, randomBytes } from 'crypto';
+import { Prisma } from '@prisma/client';
 import { PrismaService } from '../../../prisma/prisma.service';
 import { AcceptStaffInviteDto } from './dto/accept-staff-invite.dto';
 import { isUnlimitedSeats, normalizeTabPermissions } from '../../common/permissions';
@@ -399,6 +400,88 @@ export class StaffService {
     return { success: true, message: 'Member updated' };
   }
 
+  async enableMember(actorUserId: string, organizationId: string, membershipId: string) {
+    const actor = await this.getActorMembership(actorUserId, organizationId);
+    if (!actor || !this.canEditStaff(actor)) {
+      throw new ForbiddenException('You cannot manage staff');
+    }
+
+    const target = await this.prisma.membership.findFirst({
+      where: { id: membershipId, organizationId },
+      include: {
+        invitations: { orderBy: { createdAt: 'desc' }, take: 1 },
+      },
+    });
+
+    if (!target) {
+      throw new NotFoundException('Member not found');
+    }
+    if (target.isOwner) {
+      throw new ForbiddenException('Cannot enable the organization owner');
+    }
+    if (target.isActive) {
+      throw new BadRequestException('This member is already active');
+    }
+
+    const invitation = target.invitations[0];
+    if (invitation && !invitation.acceptedAt) {
+      throw new BadRequestException(
+        'This member has not completed their invitation yet. Share the invite link instead.',
+      );
+    }
+
+    await this.prisma.$transaction(async (tx) => {
+      await this.assertOrganizationHasAvailableSeat(organizationId, tx);
+      await tx.membership.update({
+        where: { id: membershipId },
+        data: { isActive: true },
+      });
+    });
+
+    return {
+      success: true,
+      message: 'Member enabled. They can sign in to this organization again.',
+    };
+  }
+
+  async disableMember(actorUserId: string, organizationId: string, membershipId: string) {
+    const actor = await this.getActorMembership(actorUserId, organizationId);
+    if (!actor || !this.canEditStaff(actor)) {
+      throw new ForbiddenException('You cannot manage staff');
+    }
+
+    const target = await this.prisma.membership.findFirst({
+      where: { id: membershipId, organizationId },
+    });
+
+    if (!target) {
+      throw new NotFoundException('Member not found');
+    }
+    if (target.isOwner) {
+      throw new ForbiddenException('Cannot disable the organization owner');
+    }
+    if (actorUserId === target.userId) {
+      throw new BadRequestException('You cannot disable your own access');
+    }
+    if (!target.isActive) {
+      throw new BadRequestException('This member is already disabled or pending activation');
+    }
+
+    await this.prisma.membership.update({
+      where: { id: membershipId },
+      data: { isActive: false },
+    });
+
+    await this.prisma.session.deleteMany({
+      where: { userId: target.userId },
+    });
+
+    return {
+      success: true,
+      message: 'Member disabled. Their seat is now available for another invite.',
+    };
+  }
+
   async removeMember(actorUserId: string, organizationId: string, membershipId: string) {
     const actor = await this.getActorMembership(actorUserId, organizationId);
     if (!actor || !this.canEditStaff(actor)) {
@@ -421,6 +504,37 @@ export class StaffService {
     return { success: true, message: 'Member removed' };
   }
 
+  private async assertOrganizationHasAvailableSeat(
+    organizationId: string,
+    db: Prisma.TransactionClient | PrismaService = this.prisma,
+  ) {
+    const org = await db.organization.findUnique({
+      where: { id: organizationId },
+      include: { plan: true },
+    });
+    if (!org) {
+      throw new NotFoundException('Organization not found');
+    }
+    if (!org.plan) {
+      throw new BadRequestException(
+        'This organization has no active subscription. Please choose a plan before adding staff.',
+      );
+    }
+
+    const maxUsers = org.plan.maxUsers;
+    const seatsUsed = await db.membership.count({
+      where: {
+        organizationId,
+        OR: [{ isOwner: true }, { isActive: true }],
+      },
+    });
+    if (!isUnlimitedSeats(maxUsers) && seatsUsed >= maxUsers) {
+      throw new BadRequestException(
+        `Your plan allows ${maxUsers} team members. Free a seat by disabling another member or upgrade your plan.`,
+      );
+    }
+  }
+
   private async getActorMembership(userId: string, organizationId: string) {
     return this.prisma.membership.findFirst({
       where: { userId, organizationId },
@@ -435,11 +549,12 @@ export class StaffService {
     isOwner: boolean;
     isActive: boolean;
     invitations: { acceptedAt: Date | null; revokedAt: Date | null; expiresAt: Date }[];
-  }): 'ACTIVE' | 'PENDING' | 'EXPIRED' {
-    if (m.isOwner || m.isActive) return 'ACTIVE';
+  }): 'ACTIVE' | 'PENDING' | 'EXPIRED' | 'DISABLED' {
+    if (m.isOwner) return 'ACTIVE';
+    if (m.isActive) return 'ACTIVE';
     const invitation = m.invitations[0];
-    if (!invitation) return 'EXPIRED';
-    if (invitation.acceptedAt) return 'ACTIVE';
+    if (invitation?.acceptedAt) return 'DISABLED';
+    if (!invitation) return 'DISABLED';
     if (invitation.revokedAt) return 'EXPIRED';
     return invitation.expiresAt.getTime() > Date.now() ? 'PENDING' : 'EXPIRED';
   }
diff --git a/frontend/src/app/(dashboard)/appointments/page.tsx b/frontend/src/app/(dashboard)/appointments/page.tsx
index 45513c8..ef0152d 100644
--- a/frontend/src/app/(dashboard)/appointments/page.tsx
+++ b/frontend/src/app/(dashboard)/appointments/page.tsx
@@ -4,7 +4,7 @@ import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { appointmentsApi } from '@/lib/api/appointments';
 import { patientsApi } from '@/lib/api/patients';
 import { useAuth } from '@/lib/hooks/useAuth';
-import { canEditAppointments, hasPermission } from '@/shared/permissions';
+import { canEditAppointments, hasPermission } from '@/components/shared/permissions';
 import type { AppointmentColumnProvider, AppointmentRecord } from '@/types/appointment';
 import type { CreatePatientInput, Patient } from '@/types/patient';
 import { CreatePatientModal } from '@/components/ui/patient/CreatePatientModal';
@@ -13,12 +13,12 @@ import { AppointmentBookingModal } from '@/components/ui/appointments/Appointmen
 import { AppointmentScheduleGrid } from '@/components/ui/appointments/AppointmentScheduleGrid';
 import { AppointmentsPatientSearch } from '@/components/ui/appointments/AppointmentsPatientSearch';
 import { AppointmentScheduleLegend } from '@/components/ui/appointments/AppointmentScheduleLegend';
-import { ScheduleDayPicker } from '@/components/ui/common/ScheduleDayPicker';
-import { ToastStack } from '@/components/ui/common/Toast';
+import { ScheduleDayPicker } from '@/components/ui/shared/ScheduleDayPicker';
+import { ToastStack } from '@/components/ui/shared/Toast';
 import { useToast } from '@/lib/hooks/useToast';
 import type { AppointmentPurpose } from '@/types/appointment';
-import { formatApiErrorMessage } from '@/lib/formatApiError';
-import { compareLocalDayStart, getLocalDayIsoRange, startOfLocalDay } from '@/lib/appointmentTime';
+import { formatApiErrorMessage } from '@/components/shared/formatApiError';
+import { compareLocalDayStart, getLocalDayIsoRange, startOfLocalDay } from '@/components/appointments/appointmentTime';
 
 const EMPTY_PATIENT_FORM: CreatePatientInput = {
   firstName: '',
@@ -273,6 +273,7 @@ export default function AppointmentsPage() {
               if (!canEditPatients) {
                 return;
               }
+              setPatientForm(EMPTY_PATIENT_FORM);
               setIsCreateOpen(true);
             }}
           />
@@ -285,7 +286,6 @@ export default function AppointmentsPage() {
           <div className="flex flex-col sm:flex-row sm:items-end gap-4 sm:justify-between">
             <ScheduleDayPicker
               value={scheduleDate}
-              minDate={todayStart}
               onChange={(d) => setScheduleDate(startOfLocalDay(d))}
             />
             {loadingSchedule && (
@@ -323,18 +323,18 @@ export default function AppointmentsPage() {
         deleting={deletingAppointment}
       />
 
-      {isCreateOpen && (
-        <div className="fixed inset-0 z-[60] flex items-center justify-center p-4 bg-black/55">
-          <CreatePatientModal
-            isOpen={isCreateOpen}
-            formData={patientForm}
-            onChange={(patch) => setPatientForm((prev) => ({ ...prev, ...patch }))}
-            onSubmit={() => void handleCreatePatient()}
-            onClose={() => setIsCreateOpen(false)}
-            loading={savingPatient}
-          />
-        </div>
-      )}
+      <CreatePatientModal
+        variant="dialog"
+        isOpen={isCreateOpen}
+        formData={patientForm}
+        onChange={(patch) => setPatientForm((prev) => ({ ...prev, ...patch }))}
+        onSubmit={() => void handleCreatePatient()}
+        onClose={() => {
+          setIsCreateOpen(false);
+          setPatientForm(EMPTY_PATIENT_FORM);
+        }}
+        loading={savingPatient}
+      />
 
     </div>
   );
diff --git a/frontend/src/app/(dashboard)/billing/page.tsx b/frontend/src/app/(dashboard)/billing/page.tsx
index b28de1c..3d90a1a 100644
--- a/frontend/src/app/(dashboard)/billing/page.tsx
+++ b/frontend/src/app/(dashboard)/billing/page.tsx
@@ -2,13 +2,13 @@
 'use client';
 import { useState } from 'react';
 import { Pencil } from 'lucide-react';
-import { Button } from '@/components/ui/common/Button';
-import { Badge } from '@/components/ui/common/Badge';
-import { Card } from '@/components/ui/common/Card';
-import { Table } from '@/components/ui/common/Table';
-import { SearchBar } from '@/components/ui/common/SearchBar';
+import { Button } from '@/components/ui/shared/Button';
+import { Badge } from '@/components/ui/shared/Badge';
+import { Card } from '@/components/ui/shared/Card';
+import { Table } from '@/components/ui/shared/Table';
+import { SearchBar } from '@/components/ui/shared/SearchBar';
 import { useAuth } from '@/lib/hooks/useAuth';
-import { hasPermission } from '@/shared/permissions';
+import { hasPermission } from '@/components/shared/permissions';
 // Mock data matching your design
 const invoices = [
     { id: '#123456', patient: 'Ali Rahmani', date: '24/9/2026', service: 'Hygiene', amount: 300, paid: 0, status: 'unpaid' },
diff --git a/frontend/src/app/(dashboard)/layout.tsx b/frontend/src/app/(dashboard)/layout.tsx
index 60af0ed..4c0978c 100644
--- a/frontend/src/app/(dashboard)/layout.tsx
+++ b/frontend/src/app/(dashboard)/layout.tsx
@@ -3,15 +3,15 @@
 import { memo, useEffect } from 'react';
 import { usePathname, useRouter } from 'next/navigation';
 import { useAuth } from '@/lib/hooks/useAuth';
-import Sidebar from '@/components/ui/common/Sidebar';
-import { ThemeToggle } from '@/components/ui/common/ThemeToggle';
+import Sidebar from '@/components/ui/shared/Sidebar';
+import { ThemeToggle } from '@/components/ui/shared/ThemeToggle';
 import { DashboardAccountMenu } from '@/components/ui/dashboard/DashboardAccountMenu';
 import {
   canAccessAppointmentsSection,
   firstAccessibleDashboardPath,
   getRequiredReadPermissionForPath,
   hasPermission,
-} from '@/shared/permissions';
+} from '@/components/shared/permissions';
 
 export default function DashboardLayout({ children }: { children: React.ReactNode }) {
   const { user, currentOrganization, isAuthReady } = useAuth();
diff --git a/frontend/src/app/(dashboard)/organizations/page.tsx b/frontend/src/app/(dashboard)/organizations/page.tsx
index d581d28..b3c9ddb 100644
--- a/frontend/src/app/(dashboard)/organizations/page.tsx
+++ b/frontend/src/app/(dashboard)/organizations/page.tsx
@@ -14,12 +14,12 @@ import {
 import { invitationTargetFromConnectionRow } from '@/components/invitations/organizationInviteLinks';
 import { CopyInvitationLinkButton } from '@/components/ui/organizations/CopyInvitationLinkButton';
 import { InvitationHistoryDialog } from '@/components/ui/organizations/InvitationHistoryDialog';
-import { Button } from '@/components/ui/common/Button';
-import { Badge, organizationConnectionStatusVariant } from '@/components/ui/common/Badge';
-import { Input } from '@/components/ui/common/Input';
-import { SearchBar } from '@/components/ui/common/SearchBar';
-import { Table } from '@/components/ui/common/Table';
-import { ToastStack } from '@/components/ui/common/Toast';
+import { Button } from '@/components/ui/shared/Button';
+import { Badge, organizationConnectionStatusVariant } from '@/components/ui/shared/Badge';
+import { Input } from '@/components/ui/shared/Input';
+import { SearchBar } from '@/components/ui/shared/SearchBar';
+import { Table } from '@/components/ui/shared/Table';
+import { ToastStack } from '@/components/ui/shared/Toast';
 import type { ApiError } from '@/types/api';
 
 function formatOrganizationStatusLabel(status: string): string {
diff --git a/frontend/src/app/(dashboard)/patients/page.tsx b/frontend/src/app/(dashboard)/patients/page.tsx
index 4095d41..9acc77f 100644
--- a/frontend/src/app/(dashboard)/patients/page.tsx
+++ b/frontend/src/app/(dashboard)/patients/page.tsx
@@ -1,10 +1,13 @@
 'use client';
 
 import { useEffect, useMemo, useState } from 'react';
-import { Button } from '@/components/ui/common/Button';
+import { Button } from '@/components/ui/shared/Button';
+import { ToastStack } from '@/components/ui/shared/Toast';
 import { patientsApi } from '@/lib/api/patients';
+import { formatApiErrorMessage } from '@/components/shared/formatApiError';
 import { useAuth } from '@/lib/hooks/useAuth';
-import { hasPermission } from '@/shared/permissions';
+import { useToast } from '@/lib/hooks/useToast';
+import { hasPermission } from '@/components/shared/permissions';
 import {
   CreatePatientInput,
   CreateTreatmentHistoryInput,
@@ -25,6 +28,7 @@ const EMPTY_PATIENT_FORM: CreatePatientInput = {
 
 export default function PatientsPage() {
   const { currentOrganization } = useAuth();
+  const toast = useToast();
   const [search, setSearch] = useState('');
   const [patients, setPatients] = useState<Patient[]>([]);
   const [selectedPatient, setSelectedPatient] = useState<Patient | undefined>();
@@ -35,8 +39,6 @@ export default function PatientsPage() {
   const [savingPatient, setSavingPatient] = useState(false);
   const [savingTreatment, setSavingTreatment] = useState(false);
   const [patientForm, setPatientForm] = useState<CreatePatientInput>(EMPTY_PATIENT_FORM);
-  const [errorMessage, setErrorMessage] = useState<string>('');
-  const [successMessage, setSuccessMessage] = useState<string>('');
   const canEditPatients = hasPermission(currentOrganization, 'TAB_PATIENTS_EDIT');
 
   const sortedPatients = useMemo(
@@ -58,21 +60,9 @@ export default function PatientsPage() {
     void loadPatients('');
   }, []);
 
-  useEffect(() => {
-    if (!successMessage) {
-      return;
-    }
-
-    const timeout = setTimeout(() => {
-      setSuccessMessage('');
-    }, 3000);
-
-    return () => clearTimeout(timeout);
-  }, [successMessage]);
-
   async function loadPatients(q: string) {
     setLoadingPatients(true);
-    setErrorMessage('');
+    toast.setError('');
     try {
       const response = await patientsApi.list({ q, page: 1, limit: 25 });
       const items = response.data.items;
@@ -82,9 +72,8 @@ export default function PatientsPage() {
         const freshSelected = items.find((item) => item.id === selectedPatient.id);
         setSelectedPatient(freshSelected);
       }
-    } catch (error: any) {
-      const message = Array.isArray(error?.message) ? error.message.join(', ') : error?.message;
-      setErrorMessage(message || 'Failed to load patients.');
+    } catch (error: unknown) {
+      toast.showError(formatApiErrorMessage(error, 'Failed to load patients.'));
     } finally {
       setLoadingPatients(false);
     }
@@ -92,13 +81,12 @@ export default function PatientsPage() {
 
   async function loadTreatments(patientId: string) {
     setLoadingTreatments(true);
-    setErrorMessage('');
+    toast.setError('');
     try {
       const response = await patientsApi.listTreatments(patientId);
       setTreatments(response.data);
-    } catch (error: any) {
-      const message = Array.isArray(error?.message) ? error.message.join(', ') : error?.message;
-      setErrorMessage(message || 'Failed to load treatment history.');
+    } catch (error: unknown) {
+      toast.showError(formatApiErrorMessage(error, 'Failed to load treatment history.'));
     } finally {
       setLoadingTreatments(false);
     }
@@ -106,8 +94,7 @@ export default function PatientsPage() {
 
   async function handleCreatePatient() {
     setSavingPatient(true);
-    setErrorMessage('');
-    setSuccessMessage('');
+    toast.setError('');
     try {
       const response = await patientsApi.create(patientForm);
       setIsCreateOpen(false);
@@ -115,12 +102,11 @@ export default function PatientsPage() {
       await loadPatients(search);
       setSelectedPatient(response.data);
       await loadTreatments(response.data.id);
-      setSuccessMessage(
+      toast.showSuccess(
         `Patient ${response.data.firstName} ${response.data.lastName} was saved successfully.`,
       );
-    } catch (error: any) {
-      const message = Array.isArray(error?.message) ? error.message.join(', ') : error?.message;
-      setErrorMessage(message || 'Failed to save patient.');
+    } catch (error: unknown) {
+      toast.showError(formatApiErrorMessage(error, 'Failed to save patient.'));
     } finally {
       setSavingPatient(false);
     }
@@ -139,29 +125,29 @@ export default function PatientsPage() {
     };
 
     setSavingTreatment(true);
-    setErrorMessage('');
-    setSuccessMessage('');
+    toast.setError('');
     try {
       await patientsApi.addTreatment(selectedPatient.id, payload);
       await loadTreatments(selectedPatient.id);
-      setSuccessMessage('Treatment entry added successfully.');
-    } catch (error: any) {
-      const message = Array.isArray(error?.message) ? error.message.join(', ') : error?.message;
-      setErrorMessage(message || 'Failed to add treatment entry.');
+      toast.showSuccess('Treatment entry added successfully.');
+    } catch (error: unknown) {
+      toast.showError(formatApiErrorMessage(error, 'Failed to add treatment entry.'));
     } finally {
       setSavingTreatment(false);
     }
   }
 
   return (
-    <div className="relative space-y-6 pb-20">
-      <div className="flex items-center justify-between">
+    <div className="space-y-6">
+      <div className="flex items-center justify-between gap-3">
         <h1 className="text-2xl font-semibold text-text-primary">Patients</h1>
         <Button
           variant="primary"
           disabled={!canEditPatients}
           onClick={() => {
             if (!canEditPatients) return;
+            toast.clear();
+            setPatientForm(EMPTY_PATIENT_FORM);
             setIsCreateOpen(true);
           }}
           title={!canEditPatients ? 'Read-only access for this organization.' : undefined}
@@ -170,14 +156,21 @@ export default function PatientsPage() {
         </Button>
       </div>
 
-      <CreatePatientModal
-        isOpen={isCreateOpen}
-        formData={patientForm}
-        onChange={(patch) => setPatientForm((prev) => ({ ...prev, ...patch }))}
-        onSubmit={handleCreatePatient}
-        onClose={() => setIsCreateOpen(false)}
-        loading={savingPatient}
-      />
+      <ToastStack {...toast.messages} />
+
+      {isCreateOpen && (
+        <CreatePatientModal
+          isOpen={isCreateOpen}
+          formData={patientForm}
+          onChange={(patch) => setPatientForm((prev) => ({ ...prev, ...patch }))}
+          onSubmit={() => void handleCreatePatient()}
+          onClose={() => {
+            setIsCreateOpen(false);
+            setPatientForm(EMPTY_PATIENT_FORM);
+          }}
+          loading={savingPatient}
+        />
+      )}
 
       <div className="grid grid-cols-1 xl:grid-cols-3 gap-6">
         <div className="xl:col-span-1">
@@ -213,21 +206,6 @@ export default function PatientsPage() {
           <TreatmentHistoryPreview items={treatments} loading={loadingTreatments} />
         </div>
       </div>
-
-      {(errorMessage || successMessage) && (
-        <div className="absolute bottom-0 left-0 right-0 z-10 w-full">
-          {errorMessage && (
-            <div className="rounded-[var(--radius-sm)] border border-red-500/50 bg-red-500/10 px-3 py-2 text-sm text-red-300 shadow-lg">
-              {errorMessage}
-            </div>
-          )}
-          {successMessage && (
-            <div className="rounded-[var(--radius-sm)] border border-emerald-500/50 bg-emerald-500/10 px-3 py-2 text-sm text-emerald-300 shadow-lg">
-              {successMessage}
-            </div>
-          )}
-        </div>
-      )}
     </div>
   );
 }
diff --git a/frontend/src/app/(dashboard)/settings/subscriptions/page.tsx b/frontend/src/app/(dashboard)/settings/subscriptions/page.tsx
index e6f6450..7116c8c 100644
--- a/frontend/src/app/(dashboard)/settings/subscriptions/page.tsx
+++ b/frontend/src/app/(dashboard)/settings/subscriptions/page.tsx
@@ -5,8 +5,8 @@ import Link from 'next/link';
 import { useRouter } from 'next/navigation';
 import { useAuth } from '@/lib/hooks/useAuth';
 import { authApi } from '@/lib/api/auth';
-import { Button } from '@/components/ui/common/Button';
-import { Toast } from '@/components/ui/common/Toast';
+import { Button } from '@/components/ui/shared/Button';
+import { Toast } from '@/components/ui/shared/Toast';
 import type { SubscriptionAlertData } from '@/types/subscription';
 
 const PLAN_OPTIONS = [
diff --git a/frontend/src/app/(dashboard)/staff/page.tsx b/frontend/src/app/(dashboard)/staff/page.tsx
index 23c60fe..0f8eb87 100644
--- a/frontend/src/app/(dashboard)/staff/page.tsx
+++ b/frontend/src/app/(dashboard)/staff/page.tsx
@@ -6,7 +6,7 @@ import {
   firstAccessibleDashboardPath,
   canEditStaff,
   canViewStaff,
-} from '@/shared/permissions';
+} from '@/components/shared/permissions';
 import {
   STAFF_FEATURE_GROUPS,
   permissionNamesFromFeatureState,
@@ -16,16 +16,18 @@ import {
   formatAccessSummary,
   type FeaturePermState,
 } from '../../../components/staff/staff-permission-form';
-import { Pencil, Trash2, Copy, Check, X } from 'lucide-react';
-import { DialogCloseButton } from '@/components/ui/common/DialogCloseButton';
+import { Pencil, Trash2, Copy, Check, X, UserX, UserCheck } from 'lucide-react';
+import { DialogCloseButton } from '@/components/ui/shared/DialogCloseButton';
 import { useAuth } from '@/lib/hooks/useAuth';
 import { staffApi, type StaffMemberDto } from '@/lib/api/staff';
-import { Button } from '@/components/ui/common/Button';
-import { Badge } from '@/components/ui/common/Badge';
-import { Input } from '@/components/ui/common/Input';
-import { Checkbox } from '@/components/ui/common/Checkbox';
-import { Table } from '@/components/ui/common/Table';
-import type { ApiError } from '@/types/api';
+import { Button } from '@/components/ui/shared/Button';
+import { Badge } from '@/components/ui/shared/Badge';
+import { Input } from '@/components/ui/shared/Input';
+import { Checkbox } from '@/components/ui/shared/Checkbox';
+import { Table } from '@/components/ui/shared/Table';
+import { ToastStack } from '@/components/ui/shared/Toast';
+import { formatApiErrorMessage } from '@/components/shared/formatApiError';
+import { useToast } from '@/lib/hooks/useToast';
 
 type StoredInviteLink = {
   membershipId: string;
@@ -54,16 +56,19 @@ function writeStoredInviteLinks(orgId: string, links: Record<string, StoredInvit
   window.localStorage.setItem(inviteLinksStorageKey(orgId), JSON.stringify(links));
 }
 
-function formatApiMessage(err: unknown): string {
-  if (!err || typeof err !== 'object') return 'Something went wrong';
-  const m = (err as ApiError).message;
-  if (Array.isArray(m)) return m.join(', ');
-  if (typeof m === 'string') return m;
-  return 'Something went wrong';
+function canShareStaffInviteLink(member: StaffMemberDto): boolean {
+  return (
+    !member.isOwner &&
+    (member.invitationStatus === 'PENDING' || member.invitationStatus === 'EXPIRED')
+  );
 }
 
-function canShareStaffInviteLink(member: StaffMemberDto): boolean {
-  return !member.isOwner && member.invitationStatus !== 'ACTIVE';
+function canDisableStaff(member: StaffMemberDto): boolean {
+  return !member.isOwner && member.isActive;
+}
+
+function canEnableStaff(member: StaffMemberDto): boolean {
+  return !member.isOwner && member.invitationStatus === 'DISABLED';
 }
 
 function PermissionGrid({
@@ -136,8 +141,7 @@ export default function StaffPage() {
     unlimited: boolean;
   } | null>(null);
   const [loading, setLoading] = useState(true);
-  const [error, setError] = useState('');
-  const [success, setSuccess] = useState('');
+  const toast = useToast();
 
   const [inviteOpen, setInviteOpen] = useState(false);
   const [inviteEmail, setInviteEmail] = useState('');
@@ -159,6 +163,10 @@ export default function StaffPage() {
   const [editName, setEditName] = useState('');
   const [editPerms, setEditPerms] = useState(() => emptyFeaturePermissionState());
   const [editLoading, setEditLoading] = useState(false);
+  const [disableTarget, setDisableTarget] = useState<StaffMemberDto | null>(null);
+  const [disablingMembershipId, setDisablingMembershipId] = useState<string | null>(null);
+  const [enableTarget, setEnableTarget] = useState<StaffMemberDto | null>(null);
+  const [enablingMembershipId, setEnablingMembershipId] = useState<string | null>(null);
 
   const canEdit = useMemo(() => canEditStaff(currentOrganization), [currentOrganization]);
   const hasActivePlan = Boolean(currentOrganization?.plan);
@@ -168,15 +176,21 @@ export default function StaffPage() {
     return seats.used >= seats.limit;
   }, [seats]);
 
+  const hasAvailableSeat = useMemo(() => {
+    if (!seats || seats.unlimited) return true;
+    if (seats.limit == null) return true;
+    return seats.used < seats.limit;
+  }, [seats]);
+
   const load = useCallback(async () => {
-    setError('');
+    toast.setError('');
     setLoading(true);
     try {
       const res = await staffApi.list();
       setMembers(res.data.members);
       setSeats(res.data.seats);
     } catch (e) {
-      setError(formatApiMessage(e));
+      toast.showError(formatApiErrorMessage(e, 'Failed to load staff.'));
     } finally {
       setLoading(false);
     }
@@ -221,17 +235,11 @@ export default function StaffPage() {
     }
   }, [currentOrganization, router]);
 
-  useEffect(() => {
-    if (!success) return;
-    const t = setTimeout(() => setSuccess(''), 4000);
-    return () => clearTimeout(t);
-  }, [success]);
-
   async function copyStaffInviteLink(member: StaffMemberDto) {
     if (!canShareStaffInviteLink(member)) return;
 
     setCopyingInviteMembershipId(member.id);
-    setError('');
+    toast.setError('');
     try {
       let invitationUrl = pendingInviteLinks[member.id]?.invitationUrl;
       if (!invitationUrl || member.invitationStatus === 'EXPIRED') {
@@ -257,7 +265,7 @@ export default function StaffPage() {
         await load();
       }
     } catch (e) {
-      setError(formatApiMessage(e));
+      toast.showError(formatApiErrorMessage(e, 'Could not copy invitation link.'));
     } finally {
       setCopyingInviteMembershipId(null);
     }
@@ -265,7 +273,7 @@ export default function StaffPage() {
 
   async function submitInvite() {
     setInviteLoading(true);
-    setError('');
+    toast.setError('');
     setLastInviteInfo(null);
     const displayName = inviteName.trim();
     const displayEmail = inviteEmail.trim();
@@ -295,14 +303,13 @@ export default function StaffPage() {
         setPendingInviteLinks(nextLinks);
         writeStoredInviteLinks(currentOrganization.id, nextLinks);
       }
-      setSuccess('');
       setInviteOpen(false);
       setInviteEmail('');
       setInviteName('');
       setInvitePerms(emptyFeaturePermissionState());
       await load();
     } catch (e) {
-      setError(formatApiMessage(e));
+      toast.showError(formatApiErrorMessage(e, 'Failed to send invitation.'));
     } finally {
       setInviteLoading(false);
     }
@@ -320,36 +327,57 @@ export default function StaffPage() {
   async function submitEdit() {
     if (!editing) return;
     setEditLoading(true);
-    setError('');
+    toast.setError('');
     try {
       await staffApi.updateMember(editing.id, {
         name: editName.trim(),
         permissionNames: permissionNamesFromFeatureState(editPerms),
       });
-      setSuccess('Member updated');
+      toast.showSuccess('Member updated.');
       setEditing(null);
       await load();
     } catch (e) {
-      setError(formatApiMessage(e));
+      toast.showError(formatApiErrorMessage(e, 'Failed to update member.'));
     } finally {
       setEditLoading(false);
     }
   }
 
-  async function removeMember(m: StaffMemberDto) {
-    if (m.isOwner) return;
-    if (m.userId === user?.id) {
-      if (!confirm('Remove yourself from this organization? You will lose access.')) return;
-    } else {
-      if (!confirm(`Remove ${m.name} from this organization?`)) return;
-    }
-    setError('');
+  function handleDeleteMember() {
+    toast.showError('Delete is not implemented yet.');
+  }
+
+  async function confirmDisableMember() {
+    if (!disableTarget || !canDisableStaff(disableTarget)) return;
+
+    setDisablingMembershipId(disableTarget.id);
+    toast.setError('');
     try {
-      await staffApi.removeMember(m.id);
-      setSuccess('Member removed');
+      await staffApi.disableMember(disableTarget.id);
+      toast.showSuccess(`${disableTarget.name} was disabled. A seat is now available.`);
+      setDisableTarget(null);
       await load();
     } catch (e) {
-      setError(formatApiMessage(e));
+      toast.showError(formatApiErrorMessage(e, 'Failed to disable member.'));
+    } finally {
+      setDisablingMembershipId(null);
+    }
+  }
+
+  async function confirmEnableMember() {
+    if (!enableTarget || !canEnableStaff(enableTarget) || !hasAvailableSeat) return;
+
+    setEnablingMembershipId(enableTarget.id);
+    toast.setError('');
+    try {
+      await staffApi.enableMember(enableTarget.id);
+      toast.showSuccess(`${enableTarget.name} was enabled and can sign in again.`);
+      setEnableTarget(null);
+      await load();
+    } catch (e) {
+      toast.showError(formatApiErrorMessage(e, 'Failed to enable member.'));
+    } finally {
+      setEnablingMembershipId(null);
     }
   }
 
@@ -383,6 +411,8 @@ export default function StaffPage() {
         </Button>
       </div>
 
+      <ToastStack {...toast.messages} />
+
       {seats && (
         <p className="text-sm text-text-secondary">
           Seats:{' '}
@@ -400,18 +430,6 @@ export default function StaffPage() {
         </p>
       )}
 
-      {error && (
-        <div className="rounded-[var(--radius-md)] border border-red-500/40 bg-red-500/10 px-4 py-3 text-sm text-red-700 dark:text-red-300">
-          {error}
-        </div>
-      )}
-
-      {success && (
-        <div className="rounded-[var(--radius-md)] border border-primary/30 bg-primary-soft/40 px-4 py-3 text-sm text-text-primary">
-          {success}
-        </div>
-      )}
-
       {lastInviteInfo && (
         <div className="relative rounded-[var(--radius-md)] border border-border-strong bg-background-secondary/90 px-4 py-3 pr-12 shadow-[inset_0_1px_0_rgba(255,255,255,0.04)] space-y-3">
           <button
@@ -453,7 +471,7 @@ export default function StaffPage() {
                   }
                   void (async () => {
                     setCopyingInviteMembershipId(lastInviteInfo.membershipId);
-                    setError('');
+                    toast.setError('');
                     try {
                       const res = await staffApi.getInvitationLink(lastInviteInfo.membershipId);
                       if (currentOrganization?.id) {
@@ -473,7 +491,7 @@ export default function StaffPage() {
                       setCopiedInviteMembershipId(lastInviteInfo.membershipId);
                       setTimeout(() => setCopiedInviteMembershipId(null), 1500);
                     } catch (e) {
-                      setError(formatApiMessage(e));
+                      toast.showError(formatApiErrorMessage(e, 'Could not copy invitation link.'));
                     } finally {
                       setCopyingInviteMembershipId(null);
                     }
@@ -501,7 +519,9 @@ export default function StaffPage() {
               <th className="px-6 py-3 text-left text-xs font-medium text-text-muted uppercase tracking-wider">Role</th>
               <th className="px-6 py-3 text-center text-xs font-medium text-text-muted uppercase tracking-wider">Status</th>
               <th className="px-6 py-3 text-left text-xs font-medium text-text-muted uppercase tracking-wider">Access</th>
-              <th className="px-6 py-3 text-right text-xs font-medium text-text-muted uppercase tracking-wider w-28">Actions</th>
+              <th className="px-6 py-3 text-center text-xs font-medium text-text-muted uppercase tracking-wider w-36">
+                Action
+              </th>
             </tr>
           }
           body={
@@ -522,6 +542,8 @@ export default function StaffPage() {
                       <Badge variant="success">Active</Badge>
                     ) : m.invitationStatus === 'PENDING' ? (
                       <Badge variant="warning">Pending</Badge>
+                    ) : m.invitationStatus === 'DISABLED' ? (
+                      <Badge variant="default">Disabled</Badge>
                     ) : (
                       <Badge variant="danger">Expired</Badge>
                     )}
@@ -535,9 +557,9 @@ export default function StaffPage() {
                       </span>
                     )}
                   </td>
-                  <td className="px-6 py-1.5 align-middle">
+                  <td className="px-6 py-1.5 align-middle text-center">
                     {!m.isOwner && (
-                      <div className="flex min-h-[36px] items-center justify-end gap-1">
+                      <div className="flex min-h-[36px] items-center justify-center gap-1 mx-auto w-fit">
                         {canShareStaffInviteLink(m) && (
                           <button
                             type="button"
@@ -554,6 +576,44 @@ export default function StaffPage() {
                             )}
                           </button>
                         )}
+                        {canEnableStaff(m) && (
+                          <button
+                            type="button"
+                            className={`p-2 rounded-md ${
+                              canEdit
+                                ? 'text-text-secondary hover:bg-background-card/80 hover:text-primary'
+                                : 'text-text-muted opacity-50 cursor-not-allowed'
+                            }`}
+                            aria-label="Enable member"
+                            disabled={!canEdit || enablingMembershipId === m.id}
+                            title="Enable member (uses a seat)"
+                            onClick={() => {
+                              if (!canEdit) return;
+                              setEnableTarget(m);
+                            }}
+                          >
+                            <UserCheck className="w-4 h-4" />
+                          </button>
+                        )}
+                        {canDisableStaff(m) && (
+                          <button
+                            type="button"
+                            className={`p-2 rounded-md ${
+                              canEdit
+                                ? 'text-text-secondary hover:bg-background-card/80 hover:text-amber-600'
+                                : 'text-text-muted opacity-50 cursor-not-allowed'
+                            }`}
+                            aria-label="Disable member"
+                            disabled={!canEdit || disablingMembershipId === m.id}
+                            title="Disable member (frees a seat)"
+                            onClick={() => {
+                              if (!canEdit) return;
+                              setDisableTarget(m);
+                            }}
+                          >
+                            <UserX className="w-4 h-4" />
+                          </button>
+                        )}
                         <button
                           type="button"
                           className={`p-2 rounded-md ${
@@ -577,11 +637,12 @@ export default function StaffPage() {
                               ? 'text-text-secondary hover:bg-red-500/15 hover:text-red-600'
                               : 'text-text-muted opacity-50 cursor-not-allowed'
                           }`}
-                          aria-label="Remove member"
+                          aria-label="Delete member"
                           disabled={!canEdit}
+                          title="Delete member (not implemented)"
                           onClick={() => {
                             if (!canEdit) return;
-                            void removeMember(m);
+                            handleDeleteMember();
                           }}
                         >
                           <Trash2 className="w-4 h-4" />
@@ -647,6 +708,120 @@ export default function StaffPage() {
         </div>
       )}
 
+      {enableTarget && (
+        <div className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/55">
+          <div
+            className="surface-card w-full max-w-md p-5 space-y-4 shadow-xl"
+            role="dialog"
+            aria-modal="true"
+            aria-labelledby="enable-staff-title"
+          >
+            <div className="flex items-start justify-between gap-2">
+              <h2 id="enable-staff-title" className="text-lg font-semibold text-text-primary pr-2">
+                Enable team member
+              </h2>
+              <DialogCloseButton
+                onClick={() => {
+                  if (enablingMembershipId) return;
+                  setEnableTarget(null);
+                }}
+              />
+            </div>
+            <p className="text-sm text-text-secondary">
+              Enable <span className="font-medium text-text-primary">{enableTarget.name}</span> (
+              {enableTarget.email})?
+            </p>
+            <ul className="text-sm text-text-secondary space-y-2 list-disc pl-5">
+              <li>They can sign in to this organization again with their existing account.</li>
+              <li>No new invitation is sent and no data was removed while they were disabled.</li>
+              <li>
+                Enabling uses <span className="text-text-primary font-medium">one seat</span> on your
+                plan.
+              </li>
+            </ul>
+            {!hasAvailableSeat && (
+              <p className="text-sm text-amber-600 dark:text-amber-400">
+                No seats are available. Disable another member or upgrade your plan before enabling
+                this person.
+              </p>
+            )}
+            <div className="flex justify-end gap-2 pt-1">
+              <Button
+                type="button"
+                variant="outline"
+                disabled={Boolean(enablingMembershipId)}
+                onClick={() => setEnableTarget(null)}
+              >
+                Cancel
+              </Button>
+              <Button
+                type="button"
+                variant="primary"
+                isLoading={enablingMembershipId === enableTarget.id}
+                disabled={Boolean(enablingMembershipId) || !hasAvailableSeat}
+                onClick={() => void confirmEnableMember()}
+              >
+                Enable member
+              </Button>
+            </div>
+          </div>
+        </div>
+      )}
+
+      {disableTarget && (
+        <div className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/55">
+          <div
+            className="surface-card w-full max-w-md p-5 space-y-4 shadow-xl"
+            role="dialog"
+            aria-modal="true"
+            aria-labelledby="disable-staff-title"
+          >
+            <div className="flex items-start justify-between gap-2">
+              <h2 id="disable-staff-title" className="text-lg font-semibold text-text-primary pr-2">
+                Disable team member
+              </h2>
+              <DialogCloseButton
+                onClick={() => {
+                  if (disablingMembershipId) return;
+                  setDisableTarget(null);
+                }}
+              />
+            </div>
+            <p className="text-sm text-text-secondary">
+              Disable <span className="font-medium text-text-primary">{disableTarget.name}</span> (
+              {disableTarget.email})?
+            </p>
+            <ul className="text-sm text-text-secondary space-y-2 list-disc pl-5">
+              <li>They will not be able to sign in to this organization.</li>
+              <li>No data will be removed.</li>
+              <li>
+                Disabling frees <span className="text-text-primary font-medium">one seat</span> on your
+                plan so you can invite someone else.
+              </li>
+            </ul>
+            <div className="flex justify-end gap-2 pt-1">
+              <Button
+                type="button"
+                variant="outline"
+                disabled={Boolean(disablingMembershipId)}
+                onClick={() => setDisableTarget(null)}
+              >
+                Cancel
+              </Button>
+              <Button
+                type="button"
+                variant="danger"
+                isLoading={disablingMembershipId === disableTarget.id}
+                disabled={Boolean(disablingMembershipId)}
+                onClick={() => void confirmDisableMember()}
+              >
+                Disable member
+              </Button>
+            </div>
+          </div>
+        </div>
+      )}
+
       {editing && (
         <div className="fixed inset-0 z-50 flex items-center justify-center p-4 bg-black/50">
           <div
diff --git a/frontend/src/app/(dashboard)/today/page.tsx b/frontend/src/app/(dashboard)/today/page.tsx
index b12f05b..9e7ecf7 100644
--- a/frontend/src/app/(dashboard)/today/page.tsx
+++ b/frontend/src/app/(dashboard)/today/page.tsx
@@ -2,7 +2,7 @@
 
 import Link from 'next/link';
 import { useAuth } from '@/lib/hooks/useAuth';
-import { Card } from '@/components/ui/common/Card';
+import { Card } from '@/components/ui/shared/Card';
 
 export default function TodayPage() {
   const { currentOrganization } = useAuth();
diff --git a/frontend/src/app/(public)/accept-invite/page.tsx b/frontend/src/app/(public)/accept-invite/page.tsx
index bfb3b3c..67f6fbb 100644
--- a/frontend/src/app/(public)/accept-invite/page.tsx
+++ b/frontend/src/app/(public)/accept-invite/page.tsx
@@ -4,8 +4,8 @@ import { useEffect, useMemo, useState } from 'react';
 import { Suspense } from 'react';
 import Link from 'next/link';
 import { useRouter, useSearchParams } from 'next/navigation';
-import { Button } from '@/components/ui/common/Button';
-import { Input } from '@/components/ui/common/Input';
+import { Button } from '@/components/ui/shared/Button';
+import { Input } from '@/components/ui/shared/Input';
 import { staffApi } from '@/lib/api/staff';
 
 function AcceptInviteContent() {
diff --git a/frontend/src/app/(public)/accept-organization-invite/page.tsx b/frontend/src/app/(public)/accept-organization-invite/page.tsx
index 2e34182..782ea2f 100644
--- a/frontend/src/app/(public)/accept-organization-invite/page.tsx
+++ b/frontend/src/app/(public)/accept-organization-invite/page.tsx
@@ -8,8 +8,8 @@ import type { OrganizationDetailsFormValues } from '@/components/ui/auth/Organiz
 import { zodResolver } from '@hookform/resolvers/zod';
 import * as z from 'zod';
 import { Lock, Mail, User } from 'lucide-react';
-import { Button } from '@/components/ui/common/Button';
-import { Input } from '@/components/ui/common/Input';
+import { Button } from '@/components/ui/shared/Button';
+import { Input } from '@/components/ui/shared/Input';
 import { OrganizationDetailsFields } from '@/components/ui/auth/OrganizationDetailsFields';
 import { RegistrationProgressSteps } from '@/components/ui/auth/RegistrationProgressSteps';
 import { organizationApi } from '@/lib/api/organization';
diff --git a/frontend/src/app/(public)/login/page.tsx b/frontend/src/app/(public)/login/page.tsx
index 280d948..a0c21ee 100644
--- a/frontend/src/app/(public)/login/page.tsx
+++ b/frontend/src/app/(public)/login/page.tsx
@@ -116,8 +116,8 @@ import Link from 'next/link';
 import { Mail, Lock } from 'lucide-react';
 
 import { useAuth } from '@/lib/hooks/useAuth';
-import { Button } from '@/components/ui/common/Button';
-import { Input } from '@/components/ui/common/Input';
+import { Button } from '@/components/ui/shared/Button';
+import { Input } from '@/components/ui/shared/Input';
 
 const loginSchema = z.object({
   email: z.string().email('Please enter a valid email address'),
diff --git a/frontend/src/app/(public)/page.tsx b/frontend/src/app/(public)/page.tsx
index be60d10..a654924 100644
--- a/frontend/src/app/(public)/page.tsx
+++ b/frontend/src/app/(public)/page.tsx
@@ -2,8 +2,8 @@
 
 import Link from 'next/link';
 import { useAuth } from '@/lib/hooks/useAuth';
-import { Button } from '@/components/ui/common/Button';
-import { ThemeToggle } from '@/components/ui/common/ThemeToggle';
+import { Button } from '@/components/ui/shared/Button';
+import { ThemeToggle } from '@/components/ui/shared/ThemeToggle';
 import { Building2, Beaker, Calendar, Shield, Clock, Users } from 'lucide-react';
 
 export default function HomePage() {
diff --git a/frontend/src/app/(public)/register/page.tsx b/frontend/src/app/(public)/register/page.tsx
index deda726..c1372fe 100644
--- a/frontend/src/app/(public)/register/page.tsx
+++ b/frontend/src/app/(public)/register/page.tsx
@@ -9,8 +9,8 @@ import { Mail, Lock, User } from 'lucide-react';
 import { useAuth } from '@/lib/hooks/useAuth';
 import { OrganizationDetailsFields } from '@/components/ui/auth/OrganizationDetailsFields';
 import { RegistrationProgressSteps } from '@/components/ui/auth/RegistrationProgressSteps';
-import { Button } from '@/components/ui/common/Button';
-import { Input } from '@/components/ui/common/Input';
+import { Button } from '@/components/ui/shared/Button';
+import { Input } from '@/components/ui/shared/Input';
 const registerSchema = z.object({
     name: z.string().min(2, 'Name must be at least 2 characters'),
     email: z.string().email('Please enter a valid email address'),
diff --git a/frontend/src/lib/appointmentOverlapLayout.ts b/frontend/src/components/appointments/appointmentOverlapLayout.ts
similarity index 100%
rename from frontend/src/lib/appointmentOverlapLayout.ts
rename to frontend/src/components/appointments/appointmentOverlapLayout.ts
diff --git a/frontend/src/lib/appointmentTime.ts b/frontend/src/components/appointments/appointmentTime.ts
similarity index 100%
rename from frontend/src/lib/appointmentTime.ts
rename to frontend/src/components/appointments/appointmentTime.ts
diff --git a/frontend/src/lib/formatApiError.ts b/frontend/src/components/shared/formatApiError.ts
similarity index 100%
rename from frontend/src/lib/formatApiError.ts
rename to frontend/src/components/shared/formatApiError.ts
diff --git a/frontend/src/components/shared/organizationTypeIcon.ts b/frontend/src/components/shared/organizationTypeIcon.ts
new file mode 100644
index 0000000..99816ab
--- /dev/null
+++ b/frontend/src/components/shared/organizationTypeIcon.ts
@@ -0,0 +1,16 @@
+import { Building2, Beaker, type LucideIcon } from 'lucide-react';
+import type { Organization } from '@/types/organization';
+
+/** Clinic → Building2, Lab → Beaker (switch-organization cards). */
+export function organizationTypeIcon(type: Organization['type']): LucideIcon {
+  return type === 'CLINIC' ? Building2 : Beaker;
+}
+
+/** Organizations tab lists counterpart orgs (labs for clinics, clinics for labs). */
+export function counterpartOrganizationType(
+  currentType: Organization['type'] | undefined,
+): Organization['type'] {
+  if (currentType === 'CLINIC') return 'LAB';
+  if (currentType === 'LAB') return 'CLINIC';
+  return 'CLINIC';
+}
diff --git a/frontend/src/shared/permissions.ts b/frontend/src/components/shared/permissions.ts
similarity index 93%
rename from frontend/src/shared/permissions.ts
rename to frontend/src/components/shared/permissions.ts
index 753e73f..2d1733c 100644
--- a/frontend/src/shared/permissions.ts
+++ b/frontend/src/components/shared/permissions.ts
@@ -16,6 +16,11 @@ export function hasPermission(org: Organization | null, permission: string): boo
   return Boolean(org.permissions?.includes(permission));
 }
 
+/** True when the user is owner of the currently selected organization. */
+export function canCreateOrganizationFromCurrentOrg(org: Organization | null): boolean {
+  return Boolean(org?.isOwner);
+}
+
 /** Sidebar / route guard: READ access to a tab */
 export function canViewTab(org: Organization | null, readPermission: string): boolean {
   return hasPermission(org, readPermission);
diff --git a/frontend/src/lib/treatmentSelection.ts b/frontend/src/components/shared/treatmentSelection.ts
similarity index 89%
rename from frontend/src/lib/treatmentSelection.ts
rename to frontend/src/components/shared/treatmentSelection.ts
index 482d00d..e3ac585 100644
--- a/frontend/src/lib/treatmentSelection.ts
+++ b/frontend/src/components/shared/treatmentSelection.ts
@@ -1,4 +1,4 @@
-import { isSameLocalCalendarDay } from '@/lib/appointmentTime';
+import { isSameLocalCalendarDay } from '@/components/appointments/appointmentTime';
 import type { TreatmentAppointment } from '@/types/treatment';
 
 /**
diff --git a/frontend/src/components/ui/appointments/AppointmentBookingModal.tsx b/frontend/src/components/ui/appointments/AppointmentBookingModal.tsx
index 08d01a5..17921df 100644
--- a/frontend/src/components/ui/appointments/AppointmentBookingModal.tsx
+++ b/frontend/src/components/ui/appointments/AppointmentBookingModal.tsx
@@ -1,9 +1,9 @@
 'use client';
 
 import { useEffect, useState } from 'react';
-import { Button } from '@/components/ui/common/Button';
-import { DialogCloseButton } from '@/components/ui/common/DialogCloseButton';
-import { Dropdown } from '@/components/ui/common/Dropdown';
+import { Button } from '@/components/ui/shared/Button';
+import { DialogCloseButton } from '@/components/ui/shared/DialogCloseButton';
+import { Dropdown } from '@/components/ui/shared/Dropdown';
 import type { AppointmentPurpose, AppointmentRecord } from '@/types/appointment';
 import { APPOINTMENT_PURPOSE_LABEL } from '@/components/ui/appointments/appointmentPurposeStyles';
 import type { Patient } from '@/types/patient';
@@ -12,7 +12,7 @@ import {
   compareLocalDayStart,
   formatTimeForInput,
   isSameLocalCalendarDay,
-} from '@/lib/appointmentTime';
+} from '@/components/appointments/appointmentTime';
 
 interface AppointmentBookingModalProps {
   open: boolean;
diff --git a/frontend/src/components/ui/appointments/AppointmentOverlapPopover.tsx b/frontend/src/components/ui/appointments/AppointmentOverlapPopover.tsx
index 01d7ec5..49cd6ad 100644
--- a/frontend/src/components/ui/appointments/AppointmentOverlapPopover.tsx
+++ b/frontend/src/components/ui/appointments/AppointmentOverlapPopover.tsx
@@ -1,7 +1,7 @@
 'use client';
 
 import { useEffect, useRef } from 'react';
-import { DialogCloseButton } from '@/components/ui/common/DialogCloseButton';
+import { DialogCloseButton } from '@/components/ui/shared/DialogCloseButton';
 import {
   APPOINTMENT_PURPOSE_LABEL,
   purposeStyle,
diff --git a/frontend/src/components/ui/appointments/AppointmentScheduleGrid.tsx b/frontend/src/components/ui/appointments/AppointmentScheduleGrid.tsx
index 13f2912..041d050 100644
--- a/frontend/src/components/ui/appointments/AppointmentScheduleGrid.tsx
+++ b/frontend/src/components/ui/appointments/AppointmentScheduleGrid.tsx
@@ -2,12 +2,12 @@
 
 import { useMemo, useState } from 'react';
 import type { AppointmentColumnProvider, AppointmentRecord } from '@/types/appointment';
-import { formatHourLabel } from '@/lib/appointmentTime';
+import { formatHourLabel } from '@/components/appointments/appointmentTime';
 import {
   computeAppointmentLaneLayouts,
   findOverlapCluster,
   lanePositionStyles,
-} from '@/lib/appointmentOverlapLayout';
+} from '@/components/appointments/appointmentOverlapLayout';
 import { purposeStyle } from '@/components/ui/appointments/appointmentPurposeStyles';
 import { AppointmentOverlapPopover } from '@/components/ui/appointments/AppointmentOverlapPopover';
 
diff --git a/frontend/src/components/ui/appointments/AppointmentsPatientSearch.tsx b/frontend/src/components/ui/appointments/AppointmentsPatientSearch.tsx
index 717528d..e0817fd 100644
--- a/frontend/src/components/ui/appointments/AppointmentsPatientSearch.tsx
+++ b/frontend/src/components/ui/appointments/AppointmentsPatientSearch.tsx
@@ -1,8 +1,8 @@
 'use client';
 
 import { Search } from 'lucide-react';
-import { Button } from '@/components/ui/common/Button';
-import { Input } from '@/components/ui/common/Input';
+import { Button } from '@/components/ui/shared/Button';
+import { Input } from '@/components/ui/shared/Input';
 import type { Patient } from '@/types/patient';
 
 interface AppointmentsPatientSearchProps {
@@ -49,7 +49,7 @@ export function AppointmentsPatientSearch({
             onClick={onAddPatient}
             title={!canAddPatient ? 'You do not have permission to add patients.' : undefined}
           >
-            + Add New Patient
+            New Patient
           </Button>
         )}
       </div>
diff --git a/frontend/src/components/ui/auth/OrganizationDetailsFields.tsx b/frontend/src/components/ui/auth/OrganizationDetailsFields.tsx
index 957646a..d4fd1de 100644
--- a/frontend/src/components/ui/auth/OrganizationDetailsFields.tsx
+++ b/frontend/src/components/ui/auth/OrganizationDetailsFields.tsx
@@ -2,7 +2,7 @@
 
 import { Building2, Mail } from 'lucide-react';
 import type { FieldErrors, UseFormRegister, UseFormSetValue } from 'react-hook-form';
-import { Input } from '@/components/ui/common/Input';
+import { Input } from '@/components/ui/shared/Input';
 
 export type OrganizationDetailsFormValues = {
   organizationName: string;
diff --git a/frontend/src/components/ui/organizations/InvitationHistoryDialog.tsx b/frontend/src/components/ui/organizations/InvitationHistoryDialog.tsx
index 1e04b42..10cd2bc 100644
--- a/frontend/src/components/ui/organizations/InvitationHistoryDialog.tsx
+++ b/frontend/src/components/ui/organizations/InvitationHistoryDialog.tsx
@@ -1,10 +1,10 @@
 'use client';
 
-import { DialogCloseButton } from '@/components/ui/common/DialogCloseButton';
-import { ToastStack, type ToastMessages } from '@/components/ui/common/Toast';
+import { DialogCloseButton } from '@/components/ui/shared/DialogCloseButton';
+import { ToastStack, type ToastMessages } from '@/components/ui/shared/Toast';
 import type { OrganizationInvitationHistoryItemDto } from '@/lib/api/organization';
-import { Badge, organizationConnectionStatusVariant } from '@/components/ui/common/Badge';
-import { Table } from '@/components/ui/common/Table';
+import { Badge, organizationConnectionStatusVariant } from '@/components/ui/shared/Badge';
+import { Table } from '@/components/ui/shared/Table';
 import { CopyInvitationLinkButton } from '@/components/ui/organizations/CopyInvitationLinkButton';
 
 function formatInvitationStatusLabel(status: OrganizationInvitationHistoryItemDto['status']): string {
diff --git a/frontend/src/components/ui/organizations/OrganizationSelectorContent.tsx b/frontend/src/components/ui/organizations/OrganizationSelectorContent.tsx
index d997d71..bfe1140 100644
--- a/frontend/src/components/ui/organizations/OrganizationSelectorContent.tsx
+++ b/frontend/src/components/ui/organizations/OrganizationSelectorContent.tsx
@@ -1,13 +1,26 @@
 'use client';
 
-import { useState } from 'react';
+import { useMemo, useState } from 'react';
 import { useAuth } from '@/lib/hooks/useAuth';
+import { canCreateOrganizationFromCurrentOrg } from '@/components/shared/permissions';
 import { Building2, Beaker, Mail } from 'lucide-react';
-import { Input } from '@/components/ui/common/Input';
-import { Button } from '@/components/ui/common/Button';
+import { Input } from '@/components/ui/shared/Input';
+import { Button } from '@/components/ui/shared/Button';
 
 export function OrganizationSelectorContent() {
-  const { organizations, selectOrganization, createOrganization, isLoading, error, clearError } = useAuth();
+  const {
+    organizations,
+    currentOrganization,
+    selectOrganization,
+    createOrganization,
+    isLoading,
+    error,
+    clearError,
+  } = useAuth();
+  const canCreateOrganization = useMemo(
+    () => canCreateOrganizationFromCurrentOrg(currentOrganization),
+    [currentOrganization],
+  );
   const [isCreateOpen, setIsCreateOpen] = useState(false);
   const [organizationName, setOrganizationName] = useState('');
   const [organizationEmail, setOrganizationEmail] = useState('');
@@ -44,22 +57,26 @@ export function OrganizationSelectorContent() {
         <div>
           <h1 className="text-3xl font-semibold text-text-primary">Organizations</h1>
           <p className="text-text-secondary mt-2">
-            Select an organization to continue, or create a new one.
+            {canCreateOrganization
+              ? 'Select an organization to continue, or create a new one.'
+              : 'Select an organization to continue.'}
           </p>
         </div>
-        <Button
-          type="button"
-          variant={isCreateOpen ? 'outline' : 'primary'}
-          onClick={() => {
-            clearError();
-            setIsCreateOpen((prev) => !prev);
-          }}
-        >
-          {isCreateOpen ? 'Cancel' : 'Create Organization'}
-        </Button>
+        {canCreateOrganization && (
+          <Button
+            type="button"
+            variant={isCreateOpen ? 'outline' : 'primary'}
+            onClick={() => {
+              clearError();
+              setIsCreateOpen((prev) => !prev);
+            }}
+          >
+            {isCreateOpen ? 'Cancel' : 'Create Organization'}
+          </Button>
+        )}
       </div>
 
-      {isCreateOpen && (
+      {canCreateOrganization && isCreateOpen && (
         <div className="surface-card p-6 space-y-4">
           <Input
             label="Organization name"
@@ -126,7 +143,11 @@ export function OrganizationSelectorContent() {
 
       {!organizations.length ? (
         <div className="surface-card p-8 text-center">
-          <p className="text-text-secondary">No organizations found. Create your first one to continue.</p>
+          <p className="text-text-secondary">
+            {canCreateOrganization
+              ? 'No organizations found. Create your first one to continue.'
+              : 'No organizations found. Ask an organization owner to invite you.'}
+          </p>
         </div>
       ) : (
         <div className="grid gap-4">
diff --git a/frontend/src/components/ui/patient/CreatePatientModal.tsx b/frontend/src/components/ui/patient/CreatePatientModal.tsx
index 6d78e63..2a52439 100644
--- a/frontend/src/components/ui/patient/CreatePatientModal.tsx
+++ b/frontend/src/components/ui/patient/CreatePatientModal.tsx
@@ -1,7 +1,8 @@
 'use client';
 
-import { Button } from '@/components/ui/common/Button';
-import { Input } from '@/components/ui/common/Input';
+import { Button } from '@/components/ui/shared/Button';
+import { DialogCloseButton } from '@/components/ui/shared/DialogCloseButton';
+import { Input } from '@/components/ui/shared/Input';
 import { CreatePatientInput } from '@/types/patient';
 
 interface CreatePatientModalProps {
@@ -11,22 +12,27 @@ interface CreatePatientModalProps {
   onSubmit: () => void;
   onClose: () => void;
   loading?: boolean;
+  /** Inline panel on Patients page; centered dialog on Appointments. */
+  variant?: 'inline' | 'dialog';
 }
 
-export function CreatePatientModal({
-  isOpen,
+function CreatePatientFormFields({
   formData,
   onChange,
   onSubmit,
   onClose,
-  loading = false,
-}: CreatePatientModalProps) {
-  if (!isOpen) {
-    return null;
-  }
-
+  loading,
+  showCancel,
+}: {
+  formData: CreatePatientInput;
+  onChange: (patch: Partial<CreatePatientInput>) => void;
+  onSubmit: () => void;
+  onClose: () => void;
+  loading: boolean;
+  showCancel: boolean;
+}) {
   return (
-    <div className="surface-card p-4 space-y-3">
+    <>
       <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
         <Input
           label="First name"
@@ -60,10 +66,80 @@ export function CreatePatientModal({
         >
           Save Patient
         </Button>
-        <Button variant="ghost" onClick={onClose}>
-          Cancel
-        </Button>
+        {showCancel && (
+          <Button variant="ghost" onClick={onClose}>
+            Cancel
+          </Button>
+        )}
       </div>
+    </>
+  );
+}
+
+export function CreatePatientModal({
+  isOpen,
+  formData,
+  onChange,
+  onSubmit,
+  onClose,
+  loading = false,
+  variant = 'inline',
+}: CreatePatientModalProps) {
+  if (!isOpen) {
+    return null;
+  }
+
+  if (variant === 'dialog') {
+    return (
+      <div
+        className="fixed inset-0 z-[60] flex items-center justify-center p-4 bg-black/55"
+        role="presentation"
+        onMouseDown={(e) => {
+          if (e.target === e.currentTarget) {
+            onClose();
+          }
+        }}
+      >
+        <div
+          className="surface-card w-full max-w-[min(56rem,calc(100vw-17rem))] p-5 space-y-4 shadow-xl"
+          role="dialog"
+          aria-modal="true"
+          aria-labelledby="create-patient-dialog-title"
+          onMouseDown={(e) => e.stopPropagation()}
+        >
+          <div className="flex items-start justify-between gap-2">
+            <h2
+              id="create-patient-dialog-title"
+              className="text-lg font-semibold text-text-primary pr-2"
+            >
+              New patient
+            </h2>
+            <DialogCloseButton onClick={onClose} />
+          </div>
+
+          <CreatePatientFormFields
+            formData={formData}
+            onChange={onChange}
+            onSubmit={onSubmit}
+            onClose={onClose}
+            loading={loading}
+            showCancel={false}
+          />
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="surface-card p-4 space-y-3">
+      <CreatePatientFormFields
+        formData={formData}
+        onChange={onChange}
+        onSubmit={onSubmit}
+        onClose={onClose}
+        loading={loading}
+        showCancel
+      />
     </div>
   );
 }
diff --git a/frontend/src/components/ui/patient/PatientSearchSelect.tsx b/frontend/src/components/ui/patient/PatientSearchSelect.tsx
index 885dbad..1041080 100644
--- a/frontend/src/components/ui/patient/PatientSearchSelect.tsx
+++ b/frontend/src/components/ui/patient/PatientSearchSelect.tsx
@@ -1,7 +1,7 @@
 'use client';
 
 import { Search } from 'lucide-react';
-import { Input } from '@/components/ui/common/Input';
+import { Input } from '@/components/ui/shared/Input';
 import { Patient } from '@/types/patient';
 
 interface PatientSearchSelectProps {
diff --git a/frontend/src/components/ui/common/Badge.tsx b/frontend/src/components/ui/shared/Badge.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Badge.tsx
rename to frontend/src/components/ui/shared/Badge.tsx
diff --git a/frontend/src/components/ui/common/Button.tsx b/frontend/src/components/ui/shared/Button.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Button.tsx
rename to frontend/src/components/ui/shared/Button.tsx
diff --git a/frontend/src/components/ui/common/Card.tsx b/frontend/src/components/ui/shared/Card.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Card.tsx
rename to frontend/src/components/ui/shared/Card.tsx
diff --git a/frontend/src/components/ui/common/Checkbox.tsx b/frontend/src/components/ui/shared/Checkbox.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Checkbox.tsx
rename to frontend/src/components/ui/shared/Checkbox.tsx
diff --git a/frontend/src/components/ui/common/DialogCloseButton.tsx b/frontend/src/components/ui/shared/DialogCloseButton.tsx
similarity index 100%
rename from frontend/src/components/ui/common/DialogCloseButton.tsx
rename to frontend/src/components/ui/shared/DialogCloseButton.tsx
diff --git a/frontend/src/components/ui/common/Dropdown.tsx b/frontend/src/components/ui/shared/Dropdown.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Dropdown.tsx
rename to frontend/src/components/ui/shared/Dropdown.tsx
diff --git a/frontend/src/components/ui/common/Input.tsx b/frontend/src/components/ui/shared/Input.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Input.tsx
rename to frontend/src/components/ui/shared/Input.tsx
diff --git a/frontend/src/components/ui/common/OrganizationCard.tsx b/frontend/src/components/ui/shared/OrganizationCard.tsx
similarity index 87%
rename from frontend/src/components/ui/common/OrganizationCard.tsx
rename to frontend/src/components/ui/shared/OrganizationCard.tsx
index 0d67055..2d785f1 100644
--- a/frontend/src/components/ui/common/OrganizationCard.tsx
+++ b/frontend/src/components/ui/shared/OrganizationCard.tsx
@@ -1,7 +1,8 @@
 // src/components/ui/OrganizationCard.tsx
 import React from 'react';
-import { Building2, Beaker, ChevronRight } from 'lucide-react';
+import { ChevronRight } from 'lucide-react';
 import type { Organization } from '@/types/organization';
+import { organizationTypeIcon } from '@/components/shared/organizationTypeIcon';
 
 interface OrganizationCardProps {
   organization: Organization;
@@ -12,7 +13,7 @@ export const OrganizationCard: React.FC<OrganizationCardProps> = ({
   organization,
   onSelect,
 }) => {
-  const Icon = organization.type === 'CLINIC' ? Building2 : Beaker;
+  const Icon = organizationTypeIcon(organization.type);
   const typeText = organization.type === 'CLINIC' ? 'Dental Clinic' : 'Dental Lab';
 
   return (
diff --git a/frontend/src/components/ui/common/ScheduleDayPicker.tsx b/frontend/src/components/ui/shared/ScheduleDayPicker.tsx
similarity index 74%
rename from frontend/src/components/ui/common/ScheduleDayPicker.tsx
rename to frontend/src/components/ui/shared/ScheduleDayPicker.tsx
index 99518f5..e91d297 100644
--- a/frontend/src/components/ui/common/ScheduleDayPicker.tsx
+++ b/frontend/src/components/ui/shared/ScheduleDayPicker.tsx
@@ -2,17 +2,11 @@
 
 import { useEffect, useId, useRef, useState } from 'react';
 import { ChevronDown, ChevronLeft, ChevronRight } from 'lucide-react';
-import {
-  addCalendarDays,
-  compareLocalDayStart,
-  startOfLocalDay,
-} from '@/lib/appointmentTime';
+import { addCalendarDays, startOfLocalDay } from '@/components/appointments/appointmentTime';
 
 interface ScheduleDayPickerProps {
   value: Date;
   onChange: (day: Date) => void;
-  /** Optional lower bound for day selection and previous-day navigation. */
-  minDate?: Date;
   label?: string;
 }
 
@@ -39,27 +33,10 @@ function buildLocalDay(year: number, month: number, day: number): Date {
   return new Date(year, month, day, 0, 0, 0, 0);
 }
 
-function clampToValidDay(
-  year: number,
-  month: number,
-  day: number,
-  min?: Date,
-): Date {
-  const maxDay = daysInMonth(year, month);
-  let next = buildLocalDay(year, month, Math.min(Math.max(1, day), maxDay));
-  if (min) {
-    const floor = startOfLocalDay(min);
-    if (compareLocalDayStart(next, floor) < 0) {
-      next = floor;
-    }
-  }
-  return next;
-}
-
-function yearRange(min?: Date, anchor?: Date): number[] {
-  const now = new Date();
-  const startYear = min ? min.getFullYear() : now.getFullYear() - 5;
-  const endYear = Math.max(now.getFullYear() + 2, anchor?.getFullYear() ?? now.getFullYear());
+function yearRange(anchor: Date): number[] {
+  const anchorYear = anchor.getFullYear();
+  const startYear = anchorYear - 10;
+  const endYear = anchorYear + 2;
   const years: number[] = [];
   for (let y = startYear; y <= endYear; y += 1) {
     years.push(y);
@@ -72,21 +49,18 @@ const selectClassName = `
   bg-background-card/90 text-text-primary text-sm
   pl-2 pr-7 py-1.5
   focus:outline-none focus:ring-2 focus:ring-primary/35 focus:border-border-strong
-  disabled:opacity-50 disabled:cursor-not-allowed
 `;
 
-export function ScheduleDayPicker({
-  value,
-  onChange,
-  minDate,
-  label = 'Schedule date',
-}: ScheduleDayPickerProps) {
+/**
+ * Calendar day navigator (arrows + year/month/day panel).
+ * Does not restrict past dates — parent pages enforce read-only vs editable for schedule grids/forms.
+ */
+export function ScheduleDayPicker({ value, onChange, label = 'Schedule date' }: ScheduleDayPickerProps) {
   const panelId = useId();
   const rootRef = useRef<HTMLDivElement>(null);
   const [panelOpen, setPanelOpen] = useState(false);
 
   const normalizedValue = startOfLocalDay(value);
-  const normalizedMin = minDate ? startOfLocalDay(minDate) : undefined;
 
   const labelText = normalizedValue.toLocaleDateString(undefined, {
     weekday: 'short',
@@ -95,28 +69,20 @@ export function ScheduleDayPicker({
     year: 'numeric',
   });
 
-  const previousDay = addCalendarDays(normalizedValue, -1);
-  const canGoPrevious =
-    !normalizedMin || compareLocalDayStart(previousDay, normalizedMin) >= 0;
-
-  const years = yearRange(normalizedMin, normalizedValue);
+  const years = yearRange(normalizedValue);
   const selectedYear = normalizedValue.getFullYear();
   const selectedMonth = normalizedValue.getMonth();
   const selectedDay = normalizedValue.getDate();
   const dayCount = daysInMonth(selectedYear, selectedMonth);
 
   function applyParts(year: number, month: number, day: number, closePanel = false) {
-    onChange(clampToValidDay(year, month, day, normalizedMin));
+    const maxDay = daysInMonth(year, month);
+    onChange(buildLocalDay(year, month, Math.min(Math.max(1, day), maxDay)));
     if (closePanel) {
       setPanelOpen(false);
     }
   }
 
-  function handlePreviousDay() {
-    if (!canGoPrevious) return;
-    onChange(previousDay);
-  }
-
   useEffect(() => {
     if (!panelOpen) return;
 
@@ -146,9 +112,8 @@ export function ScheduleDayPicker({
       <div className="flex items-center gap-1 rounded-[var(--radius-md)] border border-border bg-background-secondary/90 px-1 py-1 shadow-[inset_0_1px_0_rgba(255,255,255,0.02)]">
         <button
           type="button"
-          onClick={handlePreviousDay}
-          disabled={!canGoPrevious}
-          className="shrink-0 rounded-[var(--radius-sm)] p-2 text-text-muted hover:text-text-primary hover:bg-background-card/80 focus:outline-none focus:ring-2 focus:ring-primary/35 disabled:opacity-40 disabled:pointer-events-none"
+          onClick={() => onChange(addCalendarDays(normalizedValue, -1))}
+          className="shrink-0 rounded-[var(--radius-sm)] p-2 text-text-muted hover:text-text-primary hover:bg-background-card/80 focus:outline-none focus:ring-2 focus:ring-primary/35"
           aria-label="Previous day"
         >
           <ChevronLeft className="h-4 w-4 icon-flat" />
@@ -232,17 +197,11 @@ export function ScheduleDayPicker({
                   }
                   className={selectClassName}
                 >
-                  {MONTH_LABELS.map((name, index) => {
-                    const disabled =
-                      normalizedMin &&
-                      selectedYear === normalizedMin.getFullYear() &&
-                      index < normalizedMin.getMonth();
-                    return (
-                      <option key={name} value={index} disabled={disabled}>
-                        {name}
-                      </option>
-                    );
-                  })}
+                  {MONTH_LABELS.map((name, index) => (
+                    <option key={name} value={index}>
+                      {name}
+                    </option>
+                  ))}
                 </select>
                 <ChevronDown
                   className="pointer-events-none absolute right-1.5 top-1/2 h-3.5 w-3.5 -translate-y-1/2 text-text-muted icon-flat"
@@ -272,18 +231,11 @@ export function ScheduleDayPicker({
                   }
                   className={selectClassName}
                 >
-                  {Array.from({ length: dayCount }, (_, i) => i + 1).map((day) => {
-                    const disabled =
-                      normalizedMin &&
-                      selectedYear === normalizedMin.getFullYear() &&
-                      selectedMonth === normalizedMin.getMonth() &&
-                      day < normalizedMin.getDate();
-                    return (
-                      <option key={day} value={day} disabled={disabled}>
-                        {day}
-                      </option>
-                    );
-                  })}
+                  {Array.from({ length: dayCount }, (_, i) => i + 1).map((day) => (
+                    <option key={day} value={day}>
+                      {day}
+                    </option>
+                  ))}
                 </select>
                 <ChevronDown
                   className="pointer-events-none absolute right-1.5 top-1/2 h-3.5 w-3.5 -translate-y-1/2 text-text-muted icon-flat"
diff --git a/frontend/src/components/ui/common/SearchBar.tsx b/frontend/src/components/ui/shared/SearchBar.tsx
similarity index 100%
rename from frontend/src/components/ui/common/SearchBar.tsx
rename to frontend/src/components/ui/shared/SearchBar.tsx
diff --git a/frontend/src/components/ui/common/Sidebar.tsx b/frontend/src/components/ui/shared/Sidebar.tsx
similarity index 84%
rename from frontend/src/components/ui/common/Sidebar.tsx
rename to frontend/src/components/ui/shared/Sidebar.tsx
index 5d959bd..80bc7f8 100644
--- a/frontend/src/components/ui/common/Sidebar.tsx
+++ b/frontend/src/components/ui/shared/Sidebar.tsx
@@ -13,10 +13,14 @@ import {
   CreditCard,
 } from 'lucide-react';
 import { useAuth } from '@/lib/hooks/useAuth';
-import { canAccessAppointmentsSection, canViewTab } from '@/shared/permissions';
+import { canAccessAppointmentsSection, canViewTab } from '@/components/shared/permissions';
+import {
+  counterpartOrganizationType,
+  organizationTypeIcon,
+} from '@/components/shared/organizationTypeIcon';
 
 const menu = [
-  { name: 'Today', path: '/today', icon: LayoutDashboard, read: 'TAB_TODAY_READ' as const },
+  { name: 'Dashboard', path: '/today', icon: LayoutDashboard, read: 'TAB_TODAY_READ' as const },
   { name: 'Staff', path: '/staff', icon: UserCog, read: 'TAB_STAFF_READ' as const },
   { name: 'Patients', path: '/patients', icon: Users, read: 'TAB_PATIENTS_READ' as const },
   { name: 'Appointment', path: '/appointments', icon: Calendar, read: 'TAB_APPOINTMENTS_READ' as const },
@@ -29,6 +33,9 @@ function Sidebar() {
   const pathname = usePathname();
   const { currentOrganization } = useAuth();
   const counterpartLabel = currentOrganization?.type === 'LAB' ? 'Clinics' : 'Labs';
+  const organizationsTabIcon = organizationTypeIcon(
+    counterpartOrganizationType(currentOrganization?.type),
+  );
 
   const visibleMenu = useMemo(
     () => {
@@ -38,7 +45,7 @@ function Sidebar() {
         {
           name: counterpartLabel,
           path: '/organizations',
-          icon: FlaskConical,
+          icon: organizationsTabIcon,
           read: 'TAB_ORGANIZATIONS_READ' as const,
         },
         menu[2],
@@ -54,7 +61,7 @@ function Sidebar() {
         return canViewTab(currentOrganization, item.read);
       });
     },
-    [counterpartLabel, currentOrganization],
+    [counterpartLabel, organizationsTabIcon, currentOrganization],
   );
 
   return (
diff --git a/frontend/src/components/ui/common/Table.tsx b/frontend/src/components/ui/shared/Table.tsx
similarity index 100%
rename from frontend/src/components/ui/common/Table.tsx
rename to frontend/src/components/ui/shared/Table.tsx
diff --git a/frontend/src/components/ui/common/ThemeToggle.tsx b/frontend/src/components/ui/shared/ThemeToggle.tsx
similarity index 100%
rename from frontend/src/components/ui/common/ThemeToggle.tsx
rename to frontend/src/components/ui/shared/ThemeToggle.tsx
diff --git a/frontend/src/components/ui/common/Toast.tsx b/frontend/src/components/ui/shared/Toast.tsx
similarity index 97%
rename from frontend/src/components/ui/common/Toast.tsx
rename to frontend/src/components/ui/shared/Toast.tsx
index f3073ca..7d0e31f 100644
--- a/frontend/src/components/ui/common/Toast.tsx
+++ b/frontend/src/components/ui/shared/Toast.tsx
@@ -1,5 +1,5 @@
 import type { ReactNode } from 'react';
-import type { BadgeVariant } from '@/components/ui/common/Badge';
+import type { BadgeVariant } from '@/components/ui/shared/Badge';
 
 interface ToastProps {
   children: ReactNode;
diff --git a/frontend/src/components/ui/treatment/AppointmentsStrip.tsx b/frontend/src/components/ui/treatment/AppointmentsStrip.tsx
index b77a795..0a5cfb6 100644
--- a/frontend/src/components/ui/treatment/AppointmentsStrip.tsx
+++ b/frontend/src/components/ui/treatment/AppointmentsStrip.tsx
@@ -2,9 +2,9 @@
 
 import { CalendarDays } from 'lucide-react';
 import { purposeStyle } from '@/components/ui/appointments/appointmentPurposeStyles';
-import { Card } from '@/components/ui/common/Card';
-import { ScheduleDayPicker } from '@/components/ui/common/ScheduleDayPicker';
-import { startOfLocalDay } from '@/lib/appointmentTime';
+import { Card } from '@/components/ui/shared/Card';
+import { ScheduleDayPicker } from '@/components/ui/shared/ScheduleDayPicker';
+import { startOfLocalDay } from '@/components/appointments/appointmentTime';
 import type { TreatmentAppointment } from '@/types/treatment';
 
 interface AppointmentsStripProps {
@@ -12,8 +12,6 @@ interface AppointmentsStripProps {
   onToggleStripHidden: () => void;
   selectedDay: Date;
   onSelectDay: (day: Date) => void;
-  /** Same lower bound as Appointments schedule (cannot pick days before this). */
-  minScheduleDate: Date;
   appointments: TreatmentAppointment[];
   selectedAppointmentId: string | null;
   onSelectAppointment: (id: string) => void;
@@ -25,7 +23,6 @@ export function AppointmentsStrip({
   onToggleStripHidden,
   selectedDay,
   onSelectDay,
-  minScheduleDate,
   appointments,
   selectedAppointmentId,
   onSelectAppointment,
@@ -65,7 +62,6 @@ export function AppointmentsStrip({
       <div className="flex flex-col sm:flex-row sm:items-end gap-4 sm:justify-between">
         <ScheduleDayPicker
           value={selectedDay}
-          minDate={minScheduleDate}
           onChange={(d) => onSelectDay(startOfLocalDay(d))}
         />
         {loading && (
diff --git a/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx b/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
index 0c20616..ed39b37 100644
--- a/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
+++ b/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
@@ -4,12 +4,12 @@ import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { AppointmentsStrip } from '@/components/ui/treatment/AppointmentsStrip';
 import { FdiToothChart } from '@/components/ui/treatment/FdiToothChart';
 import { PastTreatmentsPanel } from '@/components/ui/treatment/PastTreatmentsPanel';
-import { Checkbox } from '@/components/ui/common/Checkbox';
-import { Button } from '@/components/ui/common/Button';
-import { Dropdown } from '@/components/ui/common/Dropdown';
-import { SearchBar } from '@/components/ui/common/SearchBar';
-import { Toast } from '@/components/ui/common/Toast';
-import { isSameLocalCalendarDay, startOfLocalDay } from '@/lib/appointmentTime';
+import { Checkbox } from '@/components/ui/shared/Checkbox';
+import { Button } from '@/components/ui/shared/Button';
+import { Dropdown } from '@/components/ui/shared/Dropdown';
+import { SearchBar } from '@/components/ui/shared/SearchBar';
+import { Toast } from '@/components/ui/shared/Toast';
+import { compareLocalDayStart, isSameLocalCalendarDay, startOfLocalDay } from '@/components/appointments/appointmentTime';
 import {
   fetchLinkedOrganizations,
   fetchMyAppointmentsForDay,
@@ -17,8 +17,8 @@ import {
   saveTreatmentDraft,
   sendTreatmentRecord,
 } from '@/lib/mocks/treatmentMockApi';
-import { pickAutoAppointment } from '@/lib/treatmentSelection';
-import { canEditTreatment } from '@/shared/permissions';
+import { pickAutoAppointment } from '@/components/shared/treatmentSelection';
+import { canEditTreatment } from '@/components/shared/permissions';
 import type { Organization } from '@/types/organization';
 import type {
   FdiToothId,
@@ -54,7 +54,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
 
   const [stripHidden, setStripHidden] = useState(false);
 
-  const scheduleMinDate = useMemo(() => startOfLocalDay(new Date()), []);
+  const todayStart = useMemo(() => startOfLocalDay(new Date()), []);
 
   const [selectedDay, setSelectedDay] = useState(() => startOfLocalDay(new Date()));
   const [appointments, setAppointments] = useState<TreatmentAppointment[]>([]);
@@ -87,6 +87,13 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
     [appointments, selectedAppointmentId],
   );
 
+  const isViewingPastDay = useMemo(
+    () => compareLocalDayStart(selectedDay, todayStart) < 0,
+    [selectedDay, todayStart],
+  );
+
+  const canEditTreatmentForDay = Boolean(selectedAppointment) && !isViewingPastDay;
+
   const activeRecord = useMemo(
     () => records.find((r) => r.clientId === activeRecordId) ?? records[0],
     [records, activeRecordId],
@@ -339,13 +346,19 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
         onToggleStripHidden={() => setStripHidden((s) => !s)}
         selectedDay={selectedDay}
         onSelectDay={setSelectedDay}
-        minScheduleDate={scheduleMinDate}
         appointments={appointments}
         selectedAppointmentId={selectedAppointmentId}
         onSelectAppointment={onPickAppointment}
         loading={apptsLoading}
       />
 
+      {isViewingPastDay && (
+        <p className="text-sm text-text-secondary rounded-[var(--radius-md)] border border-border/60 bg-background-secondary/50 px-3 py-2">
+          Past days are view-only. You can review appointments and history, but treatment records
+          cannot be added or changed.
+        </p>
+      )}
+
       <div className="grid grid-cols-1 xl:grid-cols-[minmax(280px,380px)_minmax(0,1fr)] gap-6 items-start">
         <div className="space-y-4">
           {selectedAppointment ? (
@@ -423,7 +436,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
           <FdiToothChart
             selected={selectedTeethSet}
             onToggle={toggleTooth}
-            disabled={!selectedAppointment}
+            disabled={!canEditTreatmentForDay}
           />
 
           <div className="surface-card p-4 space-y-4">
@@ -437,7 +450,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
               <Button
                 type="button"
                 variant="primary"
-                disabled={!selectedAppointment}
+                disabled={!canEditTreatmentForDay}
                 onClick={() => {
                   const nr = newRecord();
                   fixActiveAfterRecordsChange([...records, nr]);
@@ -486,7 +499,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
                     }}
                     placeholder="Write clinical notes for this record…"
                     rows={5}
-                    disabled={!selectedAppointment}
+                    disabled={!canEditTreatmentForDay}
                     className="mt-1.5 w-full rounded-[var(--radius-md)] border border-border bg-background-secondary/90 text-text-primary text-sm px-3 py-2 placeholder:text-text-muted focus:outline-none focus:ring-2 focus:ring-primary/35 resize-y min-h-[120px]"
                   />
                 </label>
@@ -503,7 +516,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
                         ),
                       );
                     }}
-                    disabled={!selectedAppointment}
+                    disabled={!canEditTreatmentForDay}
                     className="capitalize"
                     style={{ color: treatmentTypeTextColor }}
                   >
@@ -522,7 +535,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
                     id="treatment-record-attachments"
                     type="file"
                     multiple
-                    disabled={!selectedAppointment}
+                    disabled={!canEditTreatmentForDay}
                     onChange={(e) => {
                       addAttachments(e.target.files);
                       e.target.value = '';
@@ -533,7 +546,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
                   <Button
                     type="button"
                     variant="primary"
-                    disabled={!selectedAppointment}
+                    disabled={!canEditTreatmentForDay}
                     onClick={() => attachmentInputRef.current?.click()}
                     aria-controls="treatment-record-attachments"
                   >
@@ -589,7 +602,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
                       <Checkbox
                         key={o.id}
                         checked={activeRecord.sendToOrganizationIds.includes(o.id)}
-                        disabled={!selectedAppointment || Boolean(activeRecord.sentAt)}
+                        disabled={!canEditTreatmentForDay || Boolean(activeRecord.sentAt)}
                         onChange={(checked) => {
                           setRecords((prev) =>
                             prev.map((r) => {
@@ -614,7 +627,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
                   <Button
                     type="button"
                     variant="primary"
-                    disabled={!selectedAppointment || Boolean(activeRecord.sentAt) || sendBusyId === activeRecord.clientId}
+                    disabled={!canEditTreatmentForDay || Boolean(activeRecord.sentAt) || sendBusyId === activeRecord.clientId}
                     isLoading={sendBusyId === activeRecord.clientId}
                     onClick={() => void handleSendRecord(activeRecord)}
                   >
@@ -633,7 +646,7 @@ export function TreatmentWorkspace({ userId, currentOrganization }: TreatmentWor
               <Button
                 type="button"
                 variant="primary"
-                disabled={!selectedAppointment || saveBusy}
+                disabled={!canEditTreatmentForDay || saveBusy}
                 isLoading={saveBusy}
                 onClick={() => void handleSaveAll()}
               >
diff --git a/frontend/src/lib/api/staff.ts b/frontend/src/lib/api/staff.ts
index 1852b65..1b03460 100644
--- a/frontend/src/lib/api/staff.ts
+++ b/frontend/src/lib/api/staff.ts
@@ -7,7 +7,7 @@ export interface StaffMemberDto {
   name: string;
   isOwner: boolean;
   isActive: boolean;
-  invitationStatus: 'ACTIVE' | 'PENDING' | 'EXPIRED';
+  invitationStatus: 'ACTIVE' | 'PENDING' | 'EXPIRED' | 'DISABLED';
   invitedAt: string | null;
   acceptedAt: string | null;
   permissions: string[] | null;
@@ -100,6 +100,20 @@ export const staffApi = {
     return response.data;
   },
 
+  disableMember: async (
+    membershipId: string,
+  ): Promise<{ success: boolean; message: string }> => {
+    const response = await apiClient.patch(`/staff/members/${membershipId}/disable`);
+    return response.data;
+  },
+
+  enableMember: async (
+    membershipId: string,
+  ): Promise<{ success: boolean; message: string }> => {
+    const response = await apiClient.patch(`/staff/members/${membershipId}/enable`);
+    return response.data;
+  },
+
   removeMember: async (
     membershipId: string,
   ): Promise<{ success: boolean; message: string }> => {
diff --git a/frontend/src/lib/hooks/useToast.ts b/frontend/src/lib/hooks/useToast.ts
index 4d36e78..def906c 100644
--- a/frontend/src/lib/hooks/useToast.ts
+++ b/frontend/src/lib/hooks/useToast.ts
@@ -1,7 +1,7 @@
 'use client';
 
 import { useCallback, useEffect, useState } from 'react';
-import type { ToastMessages } from '@/components/ui/common/Toast';
+import type { ToastMessages } from '@/components/ui/shared/Toast';
 
 const DEFAULT_DURATION_MS = 4000;
 
diff --git a/frontend/src/lib/mocks/treatmentMockApi.ts b/frontend/src/lib/mocks/treatmentMockApi.ts
index 21dbff9..93d1482 100644
--- a/frontend/src/lib/mocks/treatmentMockApi.ts
+++ b/frontend/src/lib/mocks/treatmentMockApi.ts
@@ -2,7 +2,7 @@ import {
   addCalendarDays,
   isSameLocalCalendarDay,
   startOfLocalDay,
-} from '@/lib/appointmentTime';
+} from '@/components/appointments/appointmentTime';
 import type {
   FdiToothId,
   LinkedOrganizationOption,