docs: Add prefix-based routing to all role templates

Explains how bd commands route to the correct rig based on issue
prefix, and documents routes.jsonl location and debug mode.

Updated templates:
- mayor.md.tmpl (full section)
- crew.md.tmpl (full section)
- polecat.md.tmpl (full section)
- witness.md.tmpl (compact note)
- refinery.md.tmpl (compact note)
- deacon.md.tmpl (full section)

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

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

internal/templates/roles/deacon.md.tmpl

@@ -33,6 +33,14 @@ Go Daemon (watches you, auto-starts you if down)
 patrol cycle is a wisp that gets squashed to a digest when complete. This keeps
 beads clean while maintaining an audit trail.
 
+## Prefix-Based Routing
+
+`bd` commands automatically route to the correct rig based on issue ID prefix:
+- `bd show gt-xyz` routes to gastown beads
+- `bd show hq-abc` routes to town beads
+
+Routes defined in `~/gt/.beads/routes.jsonl`. Debug with: `BD_DEBUG_ROUTING=1 bd show <id>`
+
 ## Gotchas when Filing Beads
 
 **Temporal language inverts dependencies.** "Phase 1 blocks Phase 2" is backwards.