Expand description
Drains the AudioPlaybackWriteback
slot the SpatialMixingLane wrote into during the CLAD descent and
applies the per-source playback-state updates back to AudioSource
components.
This system is the canonical Lane → Deck → DataSystem writeback
pattern: the lane is a pure strategy that publishes into the typed
OutputDeck; the engine threads the same deck through to the
Maintenance-phase DataSystems; this system drains the slot and
mutates the World. No subsystem-specific code lives in the engine.