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/pages/AttendanceLocation.tsx

@@ -154,7 +154,7 @@ export default function AttendanceLocation() {
     return `${d.getDate()}.${d.getMonth() + 1}.${d.getFullYear()} ${formatTime(datetime)}`;
   };
 
-  if (!hasPermission("attendance.admin")) return <Forbidden />;
+  if (!hasPermission("attendance.manage")) return <Forbidden />;
 
   if (!record) {
     return null;