HOTFIX: bake folk into world.js POS — missing POS crashed the app boot

v9 shipped the folk genre into GENRES/TARGETS but not into app/world.js POS. With POS incomplete, app/main.js's boot runs computeGenreLayout's synchronous force-directed relaxation instead of the complete-POS early-return; that relaxation collapses the layout and crashes the WebGL renderer at load

• Fix: add folk:[1850,5750] to POS (acoustic/country cluster, min-sep clear) → POS covers all 250 genres → computeGenreLayout early-returns → clean boot.

Verified: full-app headless boot probe (real main.js) now boots with NO crash, zero console errors, 🛸 chip present, all 4 chips, starmap rendered, window.__S + GenreKernel + __STARCRUISE all live…

▶ Play it: Kettle Eschaton — parked on the genre this change names https://stellate.app/?genre=folk&seed=5851&path=1854.5710,1873.5743,1835.5743&xdur=13.122

d378711 https://github.com/aboard-io/stellate/commit/d378711b261a6da4aef229777e17e7831edabcf7