refactor(tests): enhance test infrastructure with library/collection helpers

- Add LibraryTestData struct to TestDeviceSetup
- Implement CreateLibrary() for proper library creation in tests
- Implement CreateCollection() for test collection support
- Improve test isolation with dedicated library creation

This provides a more robust foundation for integration tests that need
proper library management support.

internal/router/router.go

@@ -39,7 +39,6 @@ type Config struct {
 	LibraryHandler        *handlers.LibraryHandler
 	DeviceHandler         *handlers.DeviceHandler
 	MediaHandler          *handlers.MediaHandler
-	SearchHandler         *handlers.SearchHandler
 	MatchingHandler       *handlers.MatchingHandler
 	KOReaderHandler       *handlers.KOReaderHandler
 	WSHandler             *handlers.WSHandler