Enables bd ready --type=merge-request for MQ integration.
The Engineer can now query for ready merge-requests.
Files changed:
- cmd/bd/ready.go: Add -t/--type flag
- internal/types/types.go: Add Type field to WorkFilter
- internal/rpc/protocol.go: Add Type to ReadyArgs
- internal/storage/sqlite/ready.go: Filter by issue_type column