The app was crashing with "CANCELLED: Cancelled on client" error when
opening the app a second time. This happened because:
1. When window was reopened, old gRPC streams were in cancelled state
2. prepareForSign/prepareForKeygen tried to subscribe on cancelled streams
3. The error was unhandled and crashed the app
Changes:
- Add isConnected() check in prepareForSign() and prepareForKeygen()
- Throw meaningful error when gRPC client is not connected
- Wrap all prepareFor* calls in try-catch in main.ts
- Return user-friendly error message instead of crashing
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
hailin
d051178801
