- Ignore heartbeat events (server keep-alive pings)
- On session_sync after a reconnect: call reloadSession() to fetch
  the latest saved history so the user sees the response even if
  the agent finished while the client was disconnected
- Add chat.reloadSession(): force-reloads session from API bypassing
  the same-id guard, also restores context token metrics

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- client/ → old_webclient/ (vanilla JS client preserved as reference)
- webclient/ — new Vue 3 + Pinia webclient (source + dist build)
- vite.config.js: outDir changed to webclient/dist/
- main.py: serve /assets and /images from webclient/dist/,
  index.html from webclient/dist/index.html
- .gitignore: exclude webclient/node_modules/, include webclient/dist/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>