feat(scholars): add multiselect and bulk actions
Closing as stale: imported with the repository in March 2026 and untouched since. scholarr-legacy is the legacy repo; the branch stays, so the work can be reopened or ported if it's wanted.
scholarr: implement the frozen data-model schema
scholarr: decide D7 deletion versus re-ingestion
scholarr: decide D3 cross-source auto-attachment
scholarr: decide D4 the undo horizon
scholarr: decide D5 orphan retention
scholarr: decide D6 global identity authority
scholarr: decide D1 the public identity shape
scholarr: decide D2 unfollow retention, the favorite column, legacy read collapse, and the NEW rule