Add convoy section to understanding-gas-town, update reference.md

docs/reference.md

@@ -224,10 +224,10 @@ gt sling <bead> <rig> --molecule=<proto>
 ```bash
 gt convoy create "name" [issues...]     # Create convoy tracking issues
 gt convoy create "name" gt-a bd-b --notify mayor/  # With notification
-gt convoy add <convoy-id> <issue-id>    # Add issue (reopens if closed)
-gt convoy status [convoy-id]            # Show progress + workers (the swarm)
+gt convoy status [convoy-id]            # Show progress (🚚 hq-cv-*)
 gt convoy list                          # Dashboard of active convoys
-gt convoy list --active                 # Active only
+gt convoy list --all                    # Include landed convoys
+gt convoy list --status=closed          # Only landed convoys
 ```
 
 Note: "Swarm" is ephemeral (workers on a convoy's issues). See [Convoys](convoy.md).

docs/understanding-gas-town.md

@@ -28,6 +28,31 @@ These roles do actual project work:
 | **Crew** | Persistent worker with own clone | Long-lived, user-managed |
 | **Dog** | Deacon helper for infrastructure tasks | Ephemeral, Deacon-managed |
 
+## Convoys: Tracking Work
+
+A **convoy** (🚚) is how you track batched work in Gas Town. When you kick off work -
+even a single issue - create a convoy to track it.
+
+```bash
+# Create a convoy tracking some issues
+gt convoy create "Feature X" gt-abc gt-def --notify overseer
+
+# Check progress
+gt convoy status hq-cv-abc
+
+# Dashboard of active convoys
+gt convoy list
+```
+
+**Why convoys matter:**
+- Single view of "what's in flight"
+- Cross-rig tracking (convoy in hq-*, issues in gt-*, bd-*)
+- Auto-notification when work lands
+- Historical record of completed work (`gt convoy list --all`)
+
+The "swarm" is ephemeral - just the workers currently assigned to a convoy's issues.
+When issues close, the convoy lands. See [Convoys](convoy.md) for details.
+
 ## Crew vs Polecats
 
 Both do project work, but with key differences: