[Gastown] PR 16: Multi-Rig Support

[jrf0110]

Parent: #204 | Phase 3: Multi-Rig + Scaling

Revised: All rigs in a town share the same Town Container. Each rig's agents get their own git clones and worktrees inside the container.

Goal

A Town with multiple rigs, cross-rig mail routing, and the dashboard reflecting all rigs.

Changes

• Town DO maintains rig registry, routes cross-rig mail via Rig DO RPCs
• Dashboard shows all rigs in a town with drill-down
• Convoys can span multiple rigs
• Mayor can distribute beads across rigs based on rig capabilities/load
• All rigs in a town share the same container — each rig's agents get their own git clones and worktrees

Cross-Rig Mail Routing

When an agent in Rig A needs to communicate with an agent in Rig B:

1. Agent sends mail via gt_mail_send with target agent identity
2. Rig DO A forwards to Town DO
3. Town DO resolves target rig from agent identity
4. Town DO forwards to Rig DO B
5. Target agent receives on next gt_mail_check

Container Impact

Multiple rigs sharing one container means:

• Multiple git clones (one per rig) in /workspace/rigs/{rigId}/repo
• More worktrees, more processes
• Disk usage scales with number of rigs × repo size
• May need to scale to larger instance type or shard to container-per-rig for large towns

Dashboard Changes

• Town overview shows all rigs with summary stats
• Rig selector/navigation
• Cross-rig convoy view showing beads distributed across rigs

Dependencies

• PR 9 (Town DO)
• PR 10 (Multiple Polecats)
• PR 14 (Convoy Lifecycle)

Acceptance Criteria

• Town DO rig registry with add/remove
• Cross-rig mail routing via Town DO
• Multi-rig convoy support
• Dashboard multi-rig view with drill-down
• Mayor can distribute work across rigs
• Multiple rigs sharing container with isolated git clones

[jrf0110]

Closing — multi-rig support was implemented organically across several issues and no independent work remains.

Criteria coverage:

Criterion	Covered by
Town DO rig registry (add/remove)	#419 (Town-Centric Refactor) — rigs table in TownDO with full CRUD
Cross-rig mail routing	#441 (Beads-Centric Data Model) — mail is now type='message' beads in a single town-level table, inherently cross-rig
Multi-rig convoy support	Infrastructure done in #441; per-bead rig targeting in gt_sling_batch tracked by #540
Dashboard multi-rig view	Production UI lives in the Kilo Next.js app, covered by #346 / #225
Mayor distributes work across rigs	#419 — gt_sling accepts rig_id, gt_list_rigs exists, Mayor prompt instructs cross-rig delegation
Shared container with isolated git clones	#419 — /workspace/rigs/{rigId}/ paths, per-rig git mutex
rig_id throughout the system	#657 fixed the last remaining single-rig assumptions (refinery wrong-rig bug)