feat: Wire up created_by field for beads issues (gt-u6nri)

- Add CreatedBy field to Issue struct (matches beads GH#748)
- Add Actor field to CreateOptions, pass --actor to bd create
- Add ActorString() method to RoleInfo for identity formatting
- Update all beads.Create() callers to pass Actor
- Update direct bd create exec calls with --actor:
  - mail/router.go: uses sender identity
  - patrol_helpers.go: uses role name
  - doctor/patrol_check.go: uses "gt-doctor"
  - rig/manager.go: uses "gt-rig-init"

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

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

internal/cmd/patrol_helpers.go

@@ -117,7 +117,7 @@ func autoSpawnPatrol(cfg PatrolConfig) (string, error) {
 	}
 
 	// Create the patrol wisp
-	cmdSpawn := exec.Command("bd", "--no-daemon", "wisp", "create", protoID)
+	cmdSpawn := exec.Command("bd", "--no-daemon", "wisp", "create", protoID, "--actor", cfg.RoleName)
 	cmdSpawn.Dir = cfg.BeadsDir
 	var stdoutSpawn, stderrSpawn bytes.Buffer
 	cmdSpawn.Stdout = &stdoutSpawn