found: fade the layer across a blend instead of falling off a cliff

FOUND-AT-90% dropped the whole found layer one notch past dominance. Measured on a vaporwave->techno sweep, that left zero found events from t=0.15 to t=0.95 -- about 89% of every crossfade -- and 75% of sampled playlist tracks with no found layer at all.

• Two changes. The delete becomes an amplitude ramp: full out to t=0.1, linear to silence by 0.5, events under a small floor dropped rather than scheduled as inaudible voices.

• And a bug the cliff was hiding: genreMeta.t is the raw blend position, not distance from the nearest anchor, so testing t alone killed the layer across the entire second half of every crossfade -- including…

• FOUND_FADE_T is a named constant because the width is an ears question; no gate can settle it.

▶ Play it: Food Court Eternity — parked on the genre this change names https://stellate.app/?genre=vaporwave&seed=4594&path=1679.4393,1698.4426,1660.4426&xdur=13.122

b66fe5a https://github.com/aboard-io/stellate/commit/b66fe5a215ab510024030348162b35111ae556ff