fix: log detailed error messages in repository preflight and clone

apps/api/src/api/git_repositories.py

@@ -153,9 +153,10 @@ def _preflight_remote_repository(remote_url: str, ssh_key: SSHKey | None = None)
             os.unlink(key_path)
 
     if result.returncode != 0:
+        logger.error("Preflight check failed for %s: stderr=%s", remote_url, result.stderr)
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
-            detail="repository not found or inaccessible",
+            detail=f"repository not found or inaccessible: {result.stderr}",
         )
 
 
@@ -185,6 +186,7 @@ def _clone_working_repository(remote_url: str, repo_path: str, ssh_key: SSHKey |
             os.unlink(key_path)
 
     if result.returncode != 0:
+        logger.error("Clone failed for %s: stderr=%s", remote_url, result.stderr)
         raise HTTPException(
             status_code=status.HTTP_400_BAD_REQUEST,
             detail=f"failed to clone repository: {result.stderr}",