Fix audio breaking with console open; louder found; smarter SFX placement

Silence Csound's per-note logging (-m0 -d on all boot paths). It was console.log-ing "new alloc"/"rtevent"/amp lines for every event; with DevTools open the browser rendered the flood and janked the main thread, killing audio ("works again the moment I close the console").

• Found sound bed level 0.05 -> 0.22 so it's actually audible mixed under the band (was inaudible). Solo 0.42 -> 0.45.

• SFX build-ups (riser/sweep/downlift/reverse) now play in the FINAL bar of a section, rising into the next, instead of at the section start ("riser only makes sense as the final bar")

▶ Play it: Rail Replacement Rapture — a bed-heavy genre where the found-sound layer carries the room https://stellate.app/?genre=transitwave&seed=8663&path=749.12536,768.12569,730.12569&xdur=13.122

4a8af4f https://github.com/aboard-io/stellate/commit/4a8af4f7ddb10279797b32de26370440c35f8d4d