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

go.mod

@@ -8,7 +8,10 @@ require (
 	github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue v1.12.13
 	github.com/aws/aws-sdk-go-v2/service/dynamodb v1.26.7
 	github.com/google/uuid v1.5.0
+	github.com/gorilla/sessions v1.4.0
 	github.com/leanovate/gopter v0.2.11
+	github.com/stretchr/testify v1.11.1
+	golang.org/x/oauth2 v0.35.0
 )
 
 require (
@@ -26,9 +29,10 @@ require (
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.21.5 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sts v1.26.5 // indirect
 	github.com/aws/smithy-go v1.19.0 // indirect
+	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/gorilla/securecookie v1.1.2 // indirect
-	github.com/gorilla/sessions v1.4.0 // indirect
 	github.com/jmespath/go-jmespath v0.4.0 // indirect
-	golang.org/x/oauth2 v0.35.0 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
 	golang.org/x/sys v0.35.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
 )