tiles

The LRU-backed store of non-persistent tiles, keyed by tile-coordinate hash. Capacity comes from defaultCacheCapacity. Eviction is disabled while Timeline.isGloballyPlaying or Timeline.holdFullTimelineResidency holds so a full playback range stays resident, and a removed entry's native/GPU pixels are freed here unless that same play/hold state (or a deliberate viewport-change eviction via forceNativeFreeOnRemove) says otherwise.