* fix(daemon): validate spawn cwd asynchronously so one dead share cannot freeze every terminal
createOrAttach validated the working directory synchronously on the daemon's
only thread. Measured on Windows 11 + Ubuntu-24.04:
existsSync on an unreachable UNC share 21,022 ms
wsl.exe probe, cold distro 1,266 ms
wsl.exe probe, warm distro 59 ms
existsSync/statSync on healthy \\wsl.localhost 4 ms / 1 ms
A single unreachable share therefore blocks the whole RPC loop past the
client's 30s request ceiling, so every other terminal stalls behind it and
reports `DaemonProtocolError: Request createOrAttach timed out after 30000ms`.
The main process already validates asynchronously and passes prevalidatedCwd
(ipc/pty.ts); the daemon never got the same treatment.
Add validateWorkingDirectoryAsync (one stat, not exists-then-stat, so an
unreachable share is not paid for twice) and await it from the daemon spawn
preflights. spawnSubprocess now returns SubprocessHandle | Promise<...>, which
existing sync stubs still satisfy.
Deliberately not bounding the stat with a timeout: the 30s ceiling comes from
blocking the shared loop, not from the duration. A timeout cannot tell "slow
share" from "gone share", so it would fail spawns that succeed today at 3-8s
on a cold VPN mount, and trade an accurate "working directory does not exist"
for a guess.
The new await opened a race: it sits between the "already exists?" check and
the sessions.set that publishes the session, so two concurrent creates for one
session id both spawned. Gate creation per session id; distinct ids still spawn
in parallel.
STA-4470
* fix(daemon): fence async spawn lifecycle
Neil
OrcaWin