Add stale-attachments doctor check (gt-h6eq.4)

Implements a new doctor check that detects attached molecules that
haven't been updated in too long, which may indicate stuck work.
The check:
- Finds all pinned beads with attachments across rigs
- Checks the attached molecule's UpdatedAt timestamp
- Reports molecules in_progress with no activity for >1 hour
- Provides actionable fix hints for stuck polecats

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

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

internal/cmd/doctor.go

@@ -85,6 +85,9 @@ func runDoctor(cmd *cobra.Command, args []string) error {
 	d.Register(doctor.NewPatrolPluginsAccessibleCheck())
 	d.Register(doctor.NewPatrolRolesHavePromptsCheck())
 
+	// Attachment checks
+	d.Register(doctor.NewStaleAttachmentsCheck())
+
 	// Config architecture checks
 	d.Register(doctor.NewSettingsCheck())
 	d.Register(doctor.NewRuntimeGitignoreCheck())