- Add bd restore command to view full history of compacted issues from git
- Command temporarily checks out historical commit, reads JSONL, displays original content
- Read-only operation, no database or git state modification
- Flip ready work sort to created_at ASC (older issues first within priority tier)
- Prevents issue treadmill effect, surfaces old P1s for triage
- Update README.md and AGENTS.md with restore documentation
Closes bd-407, bd-383