v0.2.0 — no silent stalls

A run that sits queued with no worker running now says so, instead of pulsing "pending" forever. Once a run stays pending past the stalled_after threshold (default 10 seconds, null disables), the dashboard flags it: the run page shows a waiting for a queue worker panel with the command to run, the queued node turns amber, and the runs list reads "queued — no worker?". Runs parked by awaitHuman()/awaitEvent() are never flagged — waiting is what they're for.

The check is a heuristic (pending + stale updated_at) since the dashboard can't portably inspect your queue backend — but that combination has exactly one common cause.