refactor: update lifecycle mail targets from daemon/ to deacon/ (gt-5af.5)

Update all code and documentation to use deacon/ instead of daemon/
for lifecycle mail targets:

- internal/cmd/handoff.go: getManager() returns deacon/ for Mayor/Witness
- internal/daemon/lifecycle.go: ProcessLifecycleRequests uses deacon/ inbox
- docs/architecture.md: update all references in lifecycle docs
- scripts/mayor-respawn-daemon.sh: use BD_IDENTITY=deacon for mail commands

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

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

internal/daemon/lifecycle.go

@@ -19,10 +19,10 @@ type BeadsMessage struct {
 	Status      string `json:"status"`
 }
 
-// ProcessLifecycleRequests checks for and processes lifecycle requests from the daemon inbox.
+// ProcessLifecycleRequests checks for and processes lifecycle requests from the deacon inbox.
 func (d *Daemon) ProcessLifecycleRequests() {
-	// Get mail for daemon identity
-	cmd := exec.Command("bd", "mail", "inbox", "--identity", "daemon/", "--json")
+	// Get mail for deacon identity
+	cmd := exec.Command("bd", "mail", "inbox", "--identity", "deacon/", "--json")
 	cmd.Dir = d.config.TownRoot
 
 	output, err := cmd.Output()