Kill the master wobble (it lurched) + un-darken the demoscene

THE LURCH — the tape wow/flutter I added yesterday is a MODULATED DELAY — master-bus state — and fx_bus is instantiated fresh at every stream open() (stream-renderer 379/442).

• Diagnosis note: the SCORE was innocent — blend drum grids are byte-identical across the batch for 4/5 test blends, the fifth differing only by the 3 spill events the perc fix correctly removed.

THE DARK BACKGROUND — yesterday's TV pass stacked four reductions on the same layer (brightness .8->.55, deepened veil, new vignette, 4px blur) against an opacity of .45

Verified: segment-parity 10/10 byte-equal, engine, blend-arrival all PASS.

▶ Play it: Barometric Stampede — the genre that is mostly drums, so the kit has nowhere to hide https://stellate.app/?genre=jungle&seed=2494&path=1718.20504,1737.20537,1699.20537&xdur=13.122

3a59fee https://github.com/aboard-io/stellate/commit/3a59feeef08cc1029bd40a71e92ea3302b4423ac