refactor: remove unused bd pin/unpin/hook commands (bd-x0zl)

Analysis found these commands are dead code:
- gt never calls `bd pin` - uses `bd update --status=pinned` instead
- Beads.Pin() wrapper exists but is never called
- bd hook functionality duplicated by gt mol status
- Code comment says "pinned field is cosmetic for bd hook visibility"

Removed:
- cmd/bd/pin.go
- cmd/bd/unpin.go
- cmd/bd/hook.go

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

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

internal/storage/sqlite/labels.go

@@ -157,7 +157,7 @@ func (s *SQLiteStorage) GetIssuesByLabel(ctx context.Context, label string) ([]*
 	rows, err := s.db.QueryContext(ctx, `
 		SELECT i.id, i.content_hash, i.title, i.description, i.design, i.acceptance_criteria, i.notes,
 		       i.status, i.priority, i.issue_type, i.assignee, i.estimated_minutes,
-		       i.created_at, i.updated_at, i.closed_at, i.external_ref, i.source_repo, i.close_reason,
+		       i.created_at, i.created_by, i.updated_at, i.closed_at, i.external_ref, i.source_repo, i.close_reason,
 		       i.deleted_at, i.deleted_by, i.delete_reason, i.original_type,
 		       i.sender, i.ephemeral, i.pinned, i.is_template,
 		       i.await_type, i.await_id, i.timeout_ns, i.waiters