Single-photo updateMutation only invalidated, so the panel waited for
a follow-up GET /photos/{id} round-trip before showing the new value —
felt as a 200–500 ms lag after every taken_at / rating / notes edit.
Use the PATCH response (already the updated row) to merge into the
per-photo cache and patch every cached timeline list in place.
Bulk taken_at had the same shape: invalidate-only, no optimistic. When
the user dropped back from N selected to one of the modified photos
the panel briefly showed the pre-edit value. Move both bulkSetTakenAt
and bulkSetTakenAtMap into useBulkPhotoMutations alongside the rating/
color/notes pattern, with the same snapshot+patch+rollback primitives.
Tags + bulk tags still invalidate-only — separate change if needed.
abe5c1ec6b