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/molecule_attach.go

@@ -54,7 +54,7 @@ func runMoleculeAttach(cmd *cobra.Command, args []string) error {
 }
 
 // detectAgentBeadID detects the current agent's bead ID from the working directory.
-// Returns the agent bead ID (e.g., "gt-mayor", "gt-gastown-polecat-nux") or empty string if not detectable.
+// Returns the agent bead ID (e.g., "hq-mayor", "gt-gastown-polecat-nux") or empty string if not detectable.
 func detectAgentBeadID() (string, error) {
 	cwd, err := os.Getwd()
 	if err != nil {