* fix: resync session state after SSE reconnect to prevent stuck subagent UI
When a subagent completes while the page is in the background (common on
mobile PWA and desktop webview), the final SSE events are lost. The UI
then stays stuck on 'Waiting for subagent activity...' because:
- part.state.status never transitions to 'completed'
- session_status is never updated to 'idle'
- activeLatched remains true indefinitely
Fix:
- Add onReconnect callback to event pipeline, fired after SSE reconnect
- Add pageshow listener for bfcache restores (mobile PWA back-forward)
- On reconnect, re-fetch session list for directories with active sessions
- Pass explicit directory to useSessionActivity in ToolPart for subagents
to ensure the correct child store is queried
Closes#810
* fix(chat): resolve pending subagent task binding before metadata arrives
* fix: restore subagent activity and tool visibility after reconnect
- Resyncs session status and child session data after SSE reconnect
- Ensures child task tool messages are read from the correct directory
- Prevents stale assistant fallback from keeping sessions stuck as active
---------
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>
