fix(github): sync top-level copilotToken after proactive refresh (#507)

checkAndRefreshToken() updated providerSpecificData.copilotToken but
not the top-level creds.copilotToken. GithubExecutor.buildHeaders()
reads the top-level key, so every request after a proactive refresh
still sent the expired token, causing 401 "IDE token expired".

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/sse/services/tokenRefresh.js

@@ -255,6 +255,7 @@ export async function checkAndRefreshToken(provider, credentials) {
         });
 
         creds.providerSpecificData = updatedSpecific;
+        creds.copilotToken = copilotToken.token;
       }
     }
   }