Unify Convex errors and add maintenance cleanup jobs

- Add typed Convex error helpers and replace ad hoc throws
- Extract image asset helpers into shared module
- Add cron-driven cleanup for stale events and tombstones
b6409f8908Dara Adedeji committed on 7/5/2026, 6:38:30 PMparent3b044f4
28 files changedLine totals unavailable