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/routes/admin/dashboard.ts

@@ -42,8 +42,8 @@ export default async function dashboardRoutes(
       result.my_shift = { has_ongoing: myShift !== null };
     }
 
-    // Attendance admin — only for attendance.admin
-    if (has("attendance.admin")) {
+    // Attendance admin — only for attendance.manage
+    if (has("attendance.manage")) {
       const [todayAttendance, onLeaveToday, usersCount] = await Promise.all([
         prisma.attendance.findMany({
           where: {