6d11e8b3fc
Slice 10 from today-slices (d1126dd): the paste cache minted a fresh raster array per new source frame (webcam ~30 keys/s ≈ 18MB/s LOH churn → gen2 pauses that ate camera frames). Fix: _elementRasters — re-rasterize INTO the element's existing array when geometry holds, so steady-state allocation ≈ 0. The paste cache keys on (array+epoch) still protect correctness; _elementRasters[element] tracks the element's current raster so stale keys can never paste a mid-update array. MaxPasteEntries 48→256 (was a leak guard, not an allocation stream). Regression test: PasteCache_RingRecycledSources_ReRasterInPlace_WithoutAllocationChurn. Build 0 warnings, 289 tests.