fix(admin): pagination, patch tests, and per-page limits

Backend:
- Fix GetAllAdminBookingsHandler and SearchAdminBookingsHandler to
  return totalPages in response
- Auto-record patch tests when booking status progresses to "completed"
- Add GET/POST /api/admin/users/{id}/patch-tests endpoints
  Frontend:
- BookingsCard: proper pagination with 4 per page, prev/next buttons
- UsersCard, BookingCreateModal, WalkInCreateModal: per_page=4 for user
  search
- Add PatchTestModal for manual patch test entry in UserModal
- Hide patch test section when user has no eligible services
  Database:
- Add UNIQUE constraint on user_service_patch_tests(user_id, service_id)

backend/handlers/user/profile.go

@@ -553,3 +553,108 @@ func ChangePasswordHandler(w http.ResponseWriter, r *http.Request) {
 
 	w.WriteHeader(http.StatusOK)
 }
+
+type ServiceForPatchTest struct {
+	ID                     string `json:"id"`
+	Name                   string `json:"name"`
+	PatchTestDurationHours int    `json:"patchTestDurationHours"`
+}
+
+// GET /api/admin/users/{id}/patch-tests/eligible
+func GetEligiblePatchTestServicesHandler(w http.ResponseWriter, r *http.Request) {
+	userID := chi.URLParam(r, "id")
+	if userID == "" {
+		http.Error(w, "User ID is required", http.StatusBadRequest)
+		return
+	}
+
+	// Debug: count services with patch test
+	var totalWithPatchTest int
+	err := db.DB.QueryRow(r.Context(), `SELECT COUNT(*) FROM services WHERE is_active = true AND patch_test_duration_hours > 0`).Scan(&totalWithPatchTest)
+	if err != nil {
+		log.Printf("Debug: failed to count patch test services: %v", err)
+	}
+	log.Printf("Debug: userID=%s, services with patch_test=%d", userID, totalWithPatchTest)
+
+	rows, err := db.DB.Query(r.Context(), `
+		SELECT s.id, s.name, s.patch_test_duration_hours
+		FROM services s
+		WHERE s.is_active = true AND s.patch_test_duration_hours > 0
+		AND s.id NOT IN (
+			SELECT service_id FROM user_service_patch_tests WHERE user_id = $1
+		)
+		ORDER BY s.name ASC
+	`, userID)
+	if err != nil {
+		log.Printf("Failed to fetch eligible patch test services: %v", err)
+		http.Error(w, "server error", http.StatusInternalServerError)
+		return
+	}
+	defer rows.Close()
+
+	var services []ServiceForPatchTest
+	for rows.Next() {
+		var s ServiceForPatchTest
+		if err := rows.Scan(&s.ID, &s.Name, &s.PatchTestDurationHours); err != nil {
+			log.Printf("Failed to scan service: %v", err)
+			continue
+		}
+		services = append(services, s)
+	}
+
+	if services == nil {
+		services = []ServiceForPatchTest{}
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	json.NewEncoder(w).Encode(services)
+}
+
+type AddPatchTestRequest struct {
+	ServiceID string `json:"service_id"`
+}
+
+// POST /api/admin/users/{id}/patch-tests
+func AddPatchTestHandler(w http.ResponseWriter, r *http.Request) {
+	userID := chi.URLParam(r, "id")
+	if userID == "" {
+		http.Error(w, "User ID is required", http.StatusBadRequest)
+		return
+	}
+
+	var req AddPatchTestRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid request", http.StatusBadRequest)
+		return
+	}
+
+	if req.ServiceID == "" {
+		http.Error(w, "service_id is required", http.StatusBadRequest)
+		return
+	}
+
+	var patchTestHours int
+	err := db.DB.QueryRow(r.Context(), `SELECT patch_test_duration_hours FROM services WHERE id = $1 AND is_active = true AND patch_test_duration_hours > 0`, req.ServiceID).Scan(&patchTestHours)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			http.Error(w, "service not found or does not require patch test", http.StatusBadRequest)
+			return
+		}
+		log.Printf("Failed to verify service: %v", err)
+		http.Error(w, "server error", http.StatusInternalServerError)
+		return
+	}
+
+	_, err = db.DB.Exec(r.Context(), `
+		INSERT INTO user_service_patch_tests (user_id, service_id, last_time)
+		VALUES ($1, $2, NOW())
+		ON CONFLICT (user_id, service_id) DO UPDATE SET last_time = NOW()
+	`, userID, req.ServiceID)
+	if err != nil {
+		log.Printf("Failed to add patch test: %v", err)
+		http.Error(w, "failed to add patch test", http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusCreated)
+}