macOS sleep/wake (or a silent network drop) can leave the renderer's
WebSocket half-open: no close event fires, so connectionState stays
'open' while every RPC hangs until its per-call timeout. prompt.submit's
timeout is 30 minutes, so the user's next message reads as "enter does
nothing until I restart the app".
- Add a minimal ping RPC (tui_gateway/server.py) answered synchronously
on the WS reader thread.
- On wake signals, reconnectNow now probes the open-looking socket with a
5s-bounded ping and force-closes it on failure, letting the existing
reconnect machinery (backoff, tile rebinding, session refresh) take
over. A pre-ping backend answering -32601 is treated as healthy.
- Tests: half-open socket force-reconnects; healthy socket untouched;
method-not-found backend untouched; backend ping envelope contract.
Owenz-creator