docs(morning): add the pre-gig gate to the briefing — it is runnable again

MORNING.md

@@ -58,6 +58,23 @@ Set list is now data: `armada/setlist_opal2026.txt`. Reorder it and re-run to re
 
 ---
 
+## Also: the pre-gig gate can actually run now
+
+`tools/check-tracks.sh` boots every track in the set and proves each declared orbit makes
+sound — which is also the only compile check a `.tidal` file can have. It read a setlist
+from the repo root that **never existed**, so it has been unrunnable since it was written.
+Now it reads the same `armada/setlist_opal2026.txt` as the ghost report.
+
+```bash
+tools/check-tracks.sh          # ~45s per track by design; needs audio
+tools/check-tracks.sh --help
+```
+
+Worth running once with sound up before OPAL — three times this week "the rig is silent"
+turned out to be "the code did not compile".
+
+---
+
 ## Waiting on your ears / hands (not on work)
 
 1. **`pv-at --track` — run it with sound up.** It probes every control on a track and says