Surface CLI Startup Errors in the Extension
Priority: P1
Issue: #6209
StartupErrorBanner exists in webview but VS Code-native notifications for startup failures are missing.
Remaining Work
- Detect CLI process unexpected exit before port announced (
process.on('exit', ...) in ServerManager)
- Capture last N lines of stderr
- Show error notification with "Show Logs" and "Retry" buttons
- Add
'failed' state to ConnectionState
- For malformed config: parse error and show human-readable hint