fix(stt): cover 401 retry and keep proof image out of the merge diff

- parametrize the OAuth retry regression over HTTP 401 and 403 so both
  documented rejection statuses are exercised
- reword the retry-failure warning: the except block also covers the
  retried request, not just the credential refresh
- drop docs/proof/ from the PR diff; the live-proof screenshot now lives
  on the fork's proof-assets-xai-stt-oauth-retry branch and stays linked
  from the PR description

tests/tools/test_transcription_tools.py

@@ -1570,8 +1570,9 @@ class TestTranscribeXAI:
         assert "HTTP 400" in result["error"]
         assert "Invalid audio format" in result["error"]
 
-    def test_retries_403_with_refreshed_oauth_credentials(
-        self, sample_ogg, mock_xai_http_module
+    @pytest.mark.parametrize("rejected_status", [401, 403])
+    def test_retries_auth_rejection_with_refreshed_oauth_credentials(
+        self, sample_ogg, mock_xai_http_module, rejected_status
     ):
         mock_xai_http_module.resolve_xai_http_credentials.side_effect = [
             {
@@ -1587,7 +1588,7 @@ class TestTranscribeXAI:
         ]
 
         rejected = MagicMock()
-        rejected.status_code = 403
+        rejected.status_code = rejected_status
         rejected.json.return_value = {
             "error": {"message": "OAuth2 access token could not be validated"}
         }

tools/transcription_tools.py

@@ -1883,11 +1883,11 @@ def _transcribe_xai(file_path: str, model_name: str) -> Dict[str, Any]:
                         refreshed_key,
                         _resolve_base_url(refreshed_creds),
                     )
-            except Exception as refresh_exc:
+            except Exception as retry_exc:
                 logger.warning(
-                    "xAI STT OAuth refresh after HTTP %d failed: %s",
+                    "xAI STT OAuth refresh-and-retry after HTTP %d failed: %s",
                     response.status_code,
-                    refresh_exc,
+                    retry_exc,
                 )
 
         if response.status_code != 200: