improvement: notify counter badge added to treatment and tasks tabs for upadted and edited cases.

backend/prisma/schema.prisma

@@ -28,6 +28,7 @@ model User {
   assignedLabCaseTasks LabCaseTask[] @relation("LabCaseTaskAssignee")
   labCaseTaskStatusEvents LabCaseTaskStatusEvent[]
   labCaseComments LabCaseComment[]
+  labCaseActivities LabCaseActivity[]
   phoneVerificationCodes PhoneVerificationCode[]
 
   createdAt DateTime @default(now())
@@ -224,6 +225,8 @@ model LabCase {
   toothProsthesis LabCaseToothProsthesis[]
   comments        LabCaseComment[]
   attachments     LabCaseAttachment[]
+  activities      LabCaseActivity[]
+  userReadStates  LabCaseUserReadState[]
 
   @@index([treatmentId, sortOrder])
   @@map("lab_cases")
@@ -410,6 +413,60 @@ model LabCaseComment {
   @@map("lab_case_comments")
 }
 
+enum LabCaseActivityType {
+  CASE_SENT
+  CLINIC_COMMENT
+  LAB_COMMENT
+  CASE_IMPORTANT
+  CASE_AMENDED
+  TASK_COMPLETED
+}
+
+enum LabCaseTabReadTarget {
+  CASES
+  TASKS
+  TREATMENT
+}
+
+model LabCaseActivity {
+  id          String              @id @default(uuid())
+  labCaseId   String
+  type        LabCaseActivityType
+  actorUserId String?
+  payload     Json?
+  createdAt   DateTime            @default(now())
+
+  labCase   LabCase @relation(fields: [labCaseId], references: [id], onDelete: Cascade)
+  actorUser User?   @relation(fields: [actorUserId], references: [id], onDelete: SetNull)
+
+  @@index([labCaseId, createdAt])
+  @@index([type, createdAt])
+  @@map("lab_case_activities")
+}
+
+model LabCaseUserReadState {
+  userId         String
+  organizationId String
+  labCaseId      String
+  lastReadAt     DateTime
+
+  labCase LabCase @relation(fields: [labCaseId], references: [id], onDelete: Cascade)
+
+  @@id([userId, organizationId, labCaseId])
+  @@index([userId, organizationId])
+  @@map("lab_case_user_read_states")
+}
+
+model LabCaseUserTabReadState {
+  userId         String
+  organizationId String
+  tab            LabCaseTabReadTarget
+  lastReadAt     DateTime
+
+  @@id([userId, organizationId, tab])
+  @@map("lab_case_user_tab_read_states")
+}
+
 model Plan {
   id       String @id @default(uuid())
   name     String @unique // "Solo", "Small", "Medium", "Large", "Enterprise"