Add a new doctor check that verifies the bd (beads) daemon is running and healthy. When the daemon fails to start, the check: - Surfaces specific error messages (legacy database, repo mismatch) - Provides one-liner fix commands - Auto-fixes by running bd migrate --update-repo-id when appropriate This addresses GH #25: gt status slow when bd daemon not running. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>