Detect stale connections that TCP keepalive won't catch for minutes,
especially through tunnels and proxies. Pings every 30s with a 10s
pong timeout — if the client doesn't respond, the socket is terminated
and all timers cleaned up.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The HTTP resize route validates via ResizeSchema (cols: 1-500, rows:
1-200, integers only). The WS handler only checked typeof === 'number',
allowing floats, negatives, and extreme values through to ptyProcess.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Replace per-keystroke HTTP POST + SSE terminal output with a single
bidirectional WebSocket connection for dramatically lower input latency.
The existing SSE+POST paths remain fully functional as fallback.
Server-side: ws-routes.ts provides /ws/sessions/:id/terminal with 8ms
micro-batching and 16KB flush threshold. Each batch is wrapped in
DEC 2026 synchronized update markers so xterm.js renders atomically —
Ink's DA capability negotiation fails through the PTY→server→WS proxy
chain, so without server-injected markers, cursor-up redraws flicker.
Frontend: _connectWs/_disconnectWs manage per-session WS lifecycle.
Input and resize use WS fast path with HTTP POST fallback. SSE terminal
events are suppressed when WS is active to prevent double rendering.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
