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/Orders.tsx

@@ -91,6 +91,7 @@ export default function Orders() {
         queryClient.invalidateQueries({ queryKey: ["orders"] });
         queryClient.invalidateQueries({ queryKey: ["offers"] });
         queryClient.invalidateQueries({ queryKey: ["projects"] });
+        queryClient.invalidateQueries({ queryKey: ["invoices"] });
       } else {
         alert.error(result.error || "Nepodařilo se smazat objednávku");
       }