- core/index.ts: the FTS5 'search' table has no UNIQUE on id, so INSERT OR
REPLACE appended a new row every update and the search JOIN returned an id
N times. Now delete-then-insert by id -> exactly one FTS row per entity.
- taskService.claimTask: race-guarded — only an OPEN task can be claimed;
same-agent re-claim is an idempotent no-op; a task claimed by another agent or
past open is refused. getTask+updateTask are sync, so within the single-thread
event loop the read-check-write is effectively atomic (first claim wins).
- routes.ts (spec 'nicht brechen'): PATCH in_progress surfaces a lost/non-open
claim as a clean 400 instead of 500, so the board drag reverts gracefully and
a second agent can't clobber the first's claim.
- tests: +coreCorrectness.test.ts (no FTS dup after updates; concurrent claims
-> one wins; idempotent re-claim; refuse non-open) + server.test.ts route guard
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
