v1.6.5: fix attendance unique constraint, schema sync, seed script

- Change attendance idx_attendance_user_date from unique to index (allow multiple shifts per day)
- Reset migrations to single baseline init migration
- Add seed script with admin user (admin/admin)
- Update CLAUDE.md with migration workflow documentation
- Various frontend fixes (queries, pages, hooks)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/admin/lib/queries/leave.ts

@@ -1,11 +1,24 @@
 import { queryOptions } from "@tanstack/react-query";
 import { jsonQuery } from "../apiAdapter";
 
+export interface LeaveRequest {
+  id: number;
+  leave_type: string;
+  date_from: string;
+  date_to: string;
+  total_days: number;
+  total_hours: number;
+  status: string;
+  notes?: string;
+  reviewer_note?: string;
+  created_at: string;
+}
+
 export const leaveRequestsOptions = (mine = true) =>
   queryOptions({
     queryKey: ["leave-requests", mine ? "mine" : "all"],
     queryFn: () =>
-      jsonQuery<Record<string, unknown>>(
+      jsonQuery<LeaveRequest[]>(
         `/api/admin/leave-requests${mine ? "?mine=1" : ""}`,
       ),
   });