nx_iot_scene_sync_test.nx

nx_iot_scene_sync_test.nx -- gate for the lights-stay-in-sync organ. Proves the operator's "repeatable self-fixing" sync as PURE LOGIC: - sealed-enum validity - init + set_scene establishes a single source of truth (epoch bumps) - new devices start OUT of sync; resync_all converges the whole fleet - all_in_sync flips correctly; count_desynced is exact - DROP+HEAL: a device marked desynced is out of sync, then resync pulls it back -- and REPEATING the drop+heal re-fixes it every time - MEASURED syncs_restored / desyncs_seen grow with each cycle - a SCENE CHANGE knocks the whole fleet out of sync (new epoch) until re-applied -- the room re-syncs as one - idempotent add (#10); not-found / bad-arg guards expect_exit: 0 license_tier: ORIGINAL