add dleete image projects

lib/features/projects/domain/repositories/submissions_repository.dart

@@ -54,4 +54,12 @@ abstract class SubmissionsRepository {
     required String projectName,
     required String filePath,
   });
+
+  /// Delete a file from a project submission
+  /// [fileId] is the file ID to delete
+  /// [projectName] is the project name (docname)
+  Future<void> deleteProjectFile({
+    required String fileId,
+    required String projectName,
+  });
 }