Complete tasks 4.1-4.2: Page management service and HTTP endpoints

- Implemented PageService with full CRUD operations
- Added GetPages, CreatePage, UpdatePage, DeletePage, ReorderPages methods
- Cascade deletion of widgets when page is deleted
- Prevention of last page deletion
- Created page HTTP endpoints (GET, POST, PUT, DELETE, reorder)
- HTMX-friendly HTML fragment responses
- Comprehensive unit tests for service and handlers
- Updated dashboard to use PageService and create default pages

internal/handlers/dashboard_handler_test.go

@@ -6,10 +6,67 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"testing"
+	"time"
 
 	"custom-start-page/internal/middleware"
+	"custom-start-page/internal/models"
 )
 
+// mockPageService is a mock implementation of PageService for testing
+type mockPageService struct {
+	pages []*models.Page
+	err   error
+}
+
+func (m *mockPageService) GetPages(ctx context.Context, userID string) ([]*models.Page, error) {
+	if m.err != nil {
+		return nil, m.err
+	}
+	return m.pages, nil
+}
+
+func (m *mockPageService) CreatePage(ctx context.Context, userID, name string) (*models.Page, error) {
+	if m.err != nil {
+		return nil, m.err
+	}
+	page := &models.Page{
+		ID:        "new-page-id",
+		UserID:    userID,
+		Name:      name,
+		Order:     len(m.pages),
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}
+	m.pages = append(m.pages, page)
+	return page, nil
+}
+
+func (m *mockPageService) CreateDefaultPage(ctx context.Context, userID string) (*models.Page, error) {
+	return m.CreatePage(ctx, userID, "Home")
+}
+
+func (m *mockPageService) UpdatePage(ctx context.Context, userID, pageID, name string) (*models.Page, error) {
+	if m.err != nil {
+		return nil, m.err
+	}
+	for _, page := range m.pages {
+		if page.ID == pageID && page.UserID == userID {
+			page.Name = name
+			page.UpdatedAt = time.Now()
+			return page, nil
+		}
+	}
+	return nil, nil
+}
+
+func (m *mockPageService) DeletePage(ctx context.Context, userID, pageID string) error {
+	return m.err
+}
+
+func (m *mockPageService) ReorderPages(ctx context.Context, userID string, pageOrder []string) error {
+	return m.err
+}
+
 // createMockDashboardTemplate creates a simple mock template for testing
 func createMockDashboardTemplate() *template.Template {
 	tmpl := template.New("dashboard.html")
@@ -21,8 +78,21 @@ func createMockDashboardTemplate() *template.Template {
 func TestHandleDashboard_WithAuthenticatedUser(t *testing.T) {
 	// Setup
 	mockTemplate := createMockDashboardTemplate()
+	mockPages := []*models.Page{
+		{
+			ID:        "page-1",
+			UserID:    "test-user-123",
+			Name:      "Home",
+			Order:     0,
+			CreatedAt: time.Now(),
+			UpdatedAt: time.Now(),
+		},
+	}
+	mockService := &mockPageService{pages: mockPages}
+	
 	handler := &DashboardHandler{
-		templates: mockTemplate,
+		pageService: mockService,
+		templates:   mockTemplate,
 	}
 
 	// Create request with user ID in context
@@ -50,8 +120,11 @@ func TestHandleDashboard_WithAuthenticatedUser(t *testing.T) {
 func TestHandleDashboard_WithoutUserID(t *testing.T) {
 	// Setup
 	mockTemplate := createMockDashboardTemplate()
+	mockService := &mockPageService{}
+	
 	handler := &DashboardHandler{
-		templates: mockTemplate,
+		pageService: mockService,
+		templates:   mockTemplate,
 	}
 
 	// Create request without user ID in context