Speeds up task-list load and interaction for projects with 100+ tasks.
- Migration 59 adds idxTasksColumn and idxTasksUpdatedAt; listTasks()
filters by "column" on every board load and SSE/refresh paths sort by
updatedAt, so each query was previously a full table scan plus a temp
B-tree sort.
- Debounce handleEmbeddedOpenDetail in ListView so rapid keyboard/mouse
navigation no longer fires a heavy /tasks/:id (log + comments) per
selection; stale-target requests short-circuit.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>