Build 156

fix(spool): catch_unwind tick loop + PLUGKIT_VERSION env override

Watcher process was exiting after first tick on Windows because any panic
(BrokenPipe from inherited closed parent stdio, lock-poison propagation, etc.)
killed the loop. Wrap watch_once + heartbeat + status write in catch_unwind
so the daemon survives panics, recording them to errors_last_5 and a
.watcher-panic.log marker.

Also fix .status.json::binary_version which reported '0.1.3' (rs-exec crate
version baked in via env!). Read PLUGKIT_VERSION from environment so the
plugkit binary's actual version is surfaced; fall back to env! macro for
standalone use.