Spec Kitty

Mission Run: chain B consent bypass 3167

retire the dead queue-backed event drain and unblind the tests/sync cone

Priivacy-ai/spec-kitty#3167 asked for two Chain-B enforcement sites to be migrated onto the consent seam. The post-specify squad established that sync/batch.py's senders have no production caller, so migrating them would harden dead code. This mission instead retires batch_sync and sync_all_queued_events - the successor work the standing guard's own docstring nominates - and cleans the autouse fixture that blinded the tests/sync cone to that gate. sync/runtime.py:106 stays on the checkout chain per operator decision D-M5a-1=a: auto-start is not an egress boundary.