Add board service and repository, update routes and assets

- Introduced BoardService and BoardRepository for managing board-related data.
- Updated app routes to reflect the new board screen structure.
- Added new board-related assets to the asset manager.
- Refactored BoardScreen navigation to utilize the new provider structure.

lib/data/repositories/board_repositories.dart

@@ -0,0 +1,13 @@
+import '../../core/utils/result.dart';
+import '../services/board_service.dart';
+import '../services/model/board_response/board_response.dart';
+
+class BoardRepository {
+  final BoardService _boardService;
+  BoardRepository({required BoardService boardService})
+    : _boardService = boardService;
+
+  Future<Result<BoardResponse>> getBoard() async {
+    return _boardService.getBoard();
+  }
+}