execFile's `timeout` only SIGTERMs the direct shell child. A profile
that spawns a daemon (e.g. Powerlevel10k's gitstatusd under a non-TTY
GUI launch) can leave a grandchild holding the stdout pipe open, so
the execFile callback never fires and runProbe's promise hangs
forever — pinning desktop boot at "Resolving Hermes backend"
indefinitely.
Add a hard deadline that force-resolves the probe past its timeout and
kills the whole process group (shell + any daemons it spawned) so a
hung profile can never park boot.
Fixes#107109
chelsealong
00c0259bbc