fix: add missing token_uri, client_id, client_secret to OAuth 2.1 refresh store_session

The store_session call in the OAuth 2.1 credential refresh path (get_credentials)
omits token_uri, client_id, client_secret, and issuer. These are stored as None,
causing subsequent refresh attempts to fail and forcing full re-authentication.

The correct pattern already exists in three other store_session calls in the same
file (lines 151, 522, 750) — this aligns the refresh path to match.

Author: NxFerrara

auth/google_auth.py

@@ -612,9 +612,13 @@ def get_credentials(
                                     user_email=user_email,
                                     access_token=credentials.token,
                                     refresh_token=credentials.refresh_token,
+                                    token_uri=credentials.token_uri,
+                                    client_id=credentials.client_id,
+                                    client_secret=credentials.client_secret,
                                     scopes=credentials.scopes,
                                     expiry=credentials.expiry,
                                     mcp_session_id=session_id,
+                                    issuer="https://accounts.google.com",
                                 )
                                 # Persist to file so rotated refresh tokens survive restarts
                                 if not is_stateless_mode():