Two integration tests that drive the entire RFC D17 lifecycle through
the mutation composable + TanStack cache:
1. happy-path lifecycle (5 stages):
- ADD → POST /performances + Idempotency-Key
- DRAG → POST /timetable/move (target_lane=1, version bumps),
server returns cascaded[] sibling — both surface in
the resolved Promise
- RESIZE → POST /timetable/move with new end_at + new version
- PARK → POST /timetable/move with target_stage_id=null
- DELETE → DELETE /performances/p1
final wire: 4 POSTs + 1 DELETE
2. drag rollback on 409:
- server returns version_mismatch
- mutation rejects with VersionMismatchError shape
- notification.show() invoked with the Dutch toast + 'error'
Why not the full page mount: events/[id]/timetable/index.vue requires
EventTabsNav, useEventDetail, useEventChildren, multiple VTabs/VBtn/
VDialog teleports — too brittle for jsdom CI. The end-to-end + visual
flavour of this flow lives on TEST-INFRA-001's Playwright migration
backlog (and TEST-CONTRACT-001 covers the 409 path against a real
backend).
Test count: 383 → 385.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>