Add Today dashboard foundation with permission-aware KPI summary API.

Replace hardcoded Today cards with a backend summary endpoint and composable frontend widgets filtered by org type and tab permissions.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/lib/api/today.ts

@@ -0,0 +1,14 @@
+import { apiClient } from './client';
+import type { TodaySummaryResponse } from '@/types/today';
+
+export interface TodaySummaryParams {
+  from: string;
+  to: string;
+}
+
+export const todayApi = {
+  summary: async (params: TodaySummaryParams): Promise<TodaySummaryResponse> => {
+    const response = await apiClient.get('/today/summary', { params });
+    return response.data;
+  },
+};

frontend/src/lib/hooks/useTodaySummary.ts

@@ -0,0 +1,49 @@
+'use client';
+
+import { useCallback, useEffect, useState } from 'react';
+import { getLocalDayIsoRange } from '@/components/appointments/appointmentTime';
+import { todayApi } from '@/lib/api/today';
+import type { TodaySummaryData } from '@/types/today';
+import type { ApiError } from '@/types/api';
+
+interface UseTodaySummaryResult {
+  data: TodaySummaryData | null;
+  loading: boolean;
+  error: ApiError | null;
+  reload: () => Promise<void>;
+}
+
+export function useTodaySummary(enabled = true): UseTodaySummaryResult {
+  const [data, setData] = useState<TodaySummaryData | null>(null);
+  const [loading, setLoading] = useState(enabled);
+  const [error, setError] = useState<ApiError | null>(null);
+
+  const reload = useCallback(async () => {
+    if (!enabled) {
+      setData(null);
+      setLoading(false);
+      setError(null);
+      return;
+    }
+
+    setLoading(true);
+    setError(null);
+
+    try {
+      const range = getLocalDayIsoRange(new Date());
+      const response = await todayApi.summary(range);
+      setData(response.data);
+    } catch (err) {
+      setData(null);
+      setError(err as ApiError);
+    } finally {
+      setLoading(false);
+    }
+  }, [enabled]);
+
+  useEffect(() => {
+    void reload();
+  }, [reload]);
+
+  return { data, loading, error, reload };
+}