fix(final-phase): finalize dataset review audit blockers

backend/src/services/git_service.py

@@ -65,7 +65,13 @@ class GitService:
         base = Path(self.base_path)
         if base.exists() and not base.is_dir():
             raise ValueError(f"Git repositories base path is not a directory: {self.base_path}")
-        base.mkdir(parents=True, exist_ok=True)
+        try:
+            base.mkdir(parents=True, exist_ok=True)
+        except (PermissionError, OSError) as e:
+            logger.warning(
+                f"[_ensure_base_path_exists][Coherence:Failed] Cannot create Git repositories base path: {self.base_path}. Error: {e}"
+            )
+            raise ValueError(f"Cannot create Git repositories base path: {self.base_path}. {e}")
     # [/DEF:backend.src.services.git_service.GitService._ensure_base_path_exists:Function]
 
     # [DEF:backend.src.services.git_service.GitService._resolve_base_path:Function]