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/services/page_service_unit_test.go

@@ -0,0 +1,73 @@
+package services
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"custom-start-page/internal/models"
+)
+
+// TestSortPagesByOrder tests the sorting function without requiring DynamoDB
+func TestSortPagesByOrder(t *testing.T) {
+	pages := []*models.Page{
+		{ID: "page-3", Order: 2},
+		{ID: "page-1", Order: 0},
+		{ID: "page-2", Order: 1},
+	}
+
+	sortPagesByOrder(pages)
+
+	assert.Equal(t, "page-1", pages[0].ID)
+	assert.Equal(t, "page-2", pages[1].ID)
+	assert.Equal(t, "page-3", pages[2].ID)
+}
+
+// TestSortPagesByOrderAlreadySorted tests sorting already sorted pages
+func TestSortPagesByOrderAlreadySorted(t *testing.T) {
+	pages := []*models.Page{
+		{ID: "page-1", Order: 0},
+		{ID: "page-2", Order: 1},
+		{ID: "page-3", Order: 2},
+	}
+
+	sortPagesByOrder(pages)
+
+	assert.Equal(t, "page-1", pages[0].ID)
+	assert.Equal(t, "page-2", pages[1].ID)
+	assert.Equal(t, "page-3", pages[2].ID)
+}
+
+// TestSortPagesByOrderReversed tests sorting reversed pages
+func TestSortPagesByOrderReversed(t *testing.T) {
+	pages := []*models.Page{
+		{ID: "page-3", Order: 2},
+		{ID: "page-2", Order: 1},
+		{ID: "page-1", Order: 0},
+	}
+
+	sortPagesByOrder(pages)
+
+	assert.Equal(t, "page-1", pages[0].ID)
+	assert.Equal(t, "page-2", pages[1].ID)
+	assert.Equal(t, "page-3", pages[2].ID)
+}
+
+// TestSortPagesByOrderEmpty tests sorting empty slice
+func TestSortPagesByOrderEmpty(t *testing.T) {
+	pages := []*models.Page{}
+	sortPagesByOrder(pages)
+	assert.Empty(t, pages)
+}
+
+// TestSortPagesByOrderSingle tests sorting single page
+func TestSortPagesByOrderSingle(t *testing.T) {
+	pages := []*models.Page{
+		{ID: "page-1", Order: 0},
+	}
+
+	sortPagesByOrder(pages)
+
+	assert.Len(t, pages, 1)
+	assert.Equal(t, "page-1", pages[0].ID)
+}