* Robustify SSH terminal reconnect and session restore recovery
- Release the replay guard after a fallback timeout to prevent permanent
keyboard input lockouts when an unmounted terminal never parses.
- Verify backing process liveness on PTY attach and reap stale entries
so dead shells cleanly trigger a fresh pane spawn.
- Normalize connection IDs during restore to prevent spurious mismatch
errors, and treat true mismatches as expired sessions instead of crashing.
* Route disconnected SSH terminal panes through deferred connection gate
Avoid spawning SSH terminal processes against disconnected targets,
which otherwise throws "No PTY provider" and leaves panes stranded.
- Intercept spawning via a new connect gate that triggers the deferred
connection flow when the SSH target is disconnected.
- Fall back to composite worktree IDs during cold-start hydration to
ensure deferred SSH session IDs are properly stashed.
- Retry spawning and remounting terminal panes upon SSH reconnect if
they are stranded or failed to spawn.
Jinjing
Neil