docs: Make documentation convoy-first (gt-yg8bs)

Update all documentation to present convoy as the primary unit of work tracking:

- README.md: Show convoy create before sling in Quick Start and Workflows
- reference.md: Reorder to show Convoy Management before Work Assignment
- understanding-gas-town.md: Add convoy to dispatch workflow example
- mayor.md.tmpl: Add convoy commands to Work Management section
- crew.md.tmpl: Include convoy in dispatch workflow table

Convoy is now the standard workflow - all slings should be part of a convoy.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/templates/roles/crew.md.tmpl

@@ -168,7 +168,7 @@ gt worktree remove beads
 |----------|----------|
 | Quick fix in another rig | Use `gt worktree` |
 | Substantial work in another rig | Use `gt worktree` |
-| Work should be done by target rig's workers | `gt sling` to target rig |
+| Work should be done by target rig's workers | `gt convoy create` + `gt sling` to target rig |
 | Infrastructure task | Leave it to the Deacon's dogs |
 
 **Note**: Dogs are Deacon infrastructure helpers (like Boot). They're NOT for user-facing

internal/templates/roles/mayor.md.tmpl

@@ -192,9 +192,12 @@ bd show hq-abc      # Routes to town beads
 - `gt polecats <rig>` - List polecats in a rig
 
 ### Work Management
+- `gt convoy list` - Dashboard of active work (primary view)
+- `gt convoy status <id>` - Detailed convoy progress
+- `gt convoy create "name" <issues>` - Create convoy for batch work
+- `gt sling <bead> <rig>` - Assign work to polecat (auto-creates convoy)
 - `bd ready` - Issues ready to work (no blockers)
 - `bd list --status=open` - All open issues
-- `gt sling <bead> <rig>` - Assign work to polecat in rig
 
 ### Delegation
 Prefer delegating to Refineries, not directly to polecats: