Replace raw ADO.NET implementations with EF Core LINQ queries and
ExecuteUpdate/ExecuteDelete for bulk operations. TaskRepository preserves
FlipAllRunningToFailedAsync(reason) signature and keeps raw SQL for the
atomic queue claim (UPDATE...RETURNING). GetByListAsync alias kept for
backwards compat.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Data: TagRepository, ListRepository, TaskRepository (incl. queue selection via
effective agent tag + scheduled_for filter), WorktreeRepository. All CRUD via
parameterized SqliteCommand; enums roundtrip as lowercase strings matching the
schema CHECK constraints.
Worker: StaleTaskRecovery IHostedService flips running -> failed on startup and
marks the result column with a [stale] reason. All four repositories registered
as singletons.
Tests: DbFixture with temp-file SQLite + schema bootstrap, covering
TaskRepository (queue pick via list-tag and task-tag, schedule filter,
transitions, stale flip), ListRepository CRUD + junctions, and
StaleTaskRecovery. 14 tests pass.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
