refactor: migrate callers from deprecated MayorBeadID/DeaconBeadID to Town variants (gt-gbw0a)

Update all callers of deprecated MayorBeadID()/DeaconBeadID() to use
MayorBeadIDTown()/DeaconBeadIDTown() which return hq- prefix IDs for
town-level beads storage.

Changes:
- internal/daemon/lifecycle.go: identityToAgentBeadID and checkStaleAgents
- internal/cmd/prime.go: getAgentBeadID
- internal/cmd/molecule_status.go: buildAgentBeadID
- internal/cmd/prime_test.go: update expected values to hq-*
- Comments updated to reflect hq- prefix for town-level agents

The deprecated functions remain for backward compatibility and are used
by the migration tool (migrate_agents.go).

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

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

internal/cmd/prime.go

@@ -1245,14 +1245,14 @@ func getAgentFields(ctx RoleContext, state string) *beads.AgentFields {
 }
 
 // getAgentBeadID returns the agent bead ID for the current role.
-// Rig-scoped agents use the rig's configured prefix; town agents remain gt-.
+// Town-level agents (mayor, deacon) use hq- prefix; rig-scoped agents use the rig's prefix.
 // Returns empty string for unknown roles.
 func getAgentBeadID(ctx RoleContext) string {
 	switch ctx.Role {
 	case RoleMayor:
-		return beads.MayorBeadID()
+		return beads.MayorBeadIDTown()
 	case RoleDeacon:
-		return beads.DeaconBeadID()
+		return beads.DeaconBeadIDTown()
 	case RoleWitness:
 		if ctx.Rig != "" {
 			prefix := beads.GetPrefixForRig(ctx.TownRoot, ctx.Rig)