cmd_run now checks daemon.pid liveness up front: if a run loop is alive it exits
with an error (protecting the single-launcher invariant locking depends on); a
stale daemon.pid (dead pid) is cleared and the run proceeds.
Replace live_workers with reservation-aware active_workers + shared _meta_active:
a job counts toward --max the moment its meta is written (before the worker is
backgrounded), so --max can never be exceeded. A <30s guard prevents a meta
orphaned mid-launch from pinning a slot. busy_keys now shares _meta_active.
Mark a running worker '⚠ stalled' when its log has not changed for more than
AGENT_QUEUE_STALL_MIN minutes (default 10), using log mtime as the freshness
signal. Implemented in both the bash status table and the Node dashboard.
Honor 'timeout: 45m' (90s|45m|2h|1d) by wrapping the agent in timeout/gtimeout
when available (hard process-tree kill), else a portable bash watchdog. On expiry
the job moves doing->failed with result=timeout and a TIMED OUT log line.
Serialize jobs by lock key (frontmatter 'lock:' override, default cwd) via the
single run-loop's pre-launch eligibility check; the oldest non-busy job is picked
regardless of --max. Adds a flock-based worker guard where flock exists (Linux);
macOS relies on the single-daemon model. Records lock= in job meta.
