refactor: use hq- prefix for role bead references

Migrate all role bead references from gt-*-role to hq-*-role using
beads.RoleBeadIDTown() function. Role beads are stored in town beads
(~/gt/.beads/) with the hq- prefix.

Changes:
- internal/cmd/prime.go: Use RoleBeadIDTown() for all roles
- internal/doctor/agent_beads_check.go: Use RoleBeadIDTown() for rig agents
- internal/polecat/manager.go: Use RoleBeadIDTown("polecat")
- internal/cmd/crew_add.go: Use RoleBeadIDTown("crew")
- internal/beads/beads.go: Update comments to document hq- convention
- Templates: Update bd show gt-deacon to bd show hq-deacon

Note: Tmux session names remain as gt-* (runtime identifiers).
Bead IDs use hq-* for town-level agents (persistent storage).

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

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

internal/beads/beads.go

@@ -1388,15 +1388,20 @@ func IsAgentSessionBead(beadID string) bool {
 }
 
 // Role bead ID naming convention:
-//   gt-<role>-role
+// Role beads are stored in town beads (~/.beads/) with hq- prefix.
+//
+// Canonical format: hq-<role>-role
 //
 // Examples:
-//   - gt-mayor-role
-//   - gt-deacon-role
-//   - gt-witness-role
-//   - gt-refinery-role
-//   - gt-crew-role
-//   - gt-polecat-role
+//   - hq-mayor-role
+//   - hq-deacon-role
+//   - hq-witness-role
+//   - hq-refinery-role
+//   - hq-crew-role
+//   - hq-polecat-role
+//
+// Use RoleBeadIDTown() to get canonical role bead IDs.
+// The legacy RoleBeadID() function returns gt-<role>-role for backward compatibility.
 
 // RoleBeadID returns the role bead ID for a given role type.
 // Role beads define lifecycle configuration for each agent type.