Explorer: continuous blend weights (no midpoint snap) + 4 UI fixes

THE BUG — weightsAt() hard-snapped to the nearest anchor inside SNAP=26px. arabpop and triphop sit ~39 logical px apart, so their snap radii OVERLAP

UI — path points 2x (halo 14->28, dot 9->18, numbers 11->22px); labels hold WHITE for 10s after the last interaction (single reset timer, no leak)

Verified: live smoke PASS (load 0.987, L/R balance 0.939, 0 errors); full headless session tap->zoom->pan->draw->play across a leg boundary, 0 console errors.

▶ Play it: Inclement Surveillance → Sirocco Telemetry → Dune Recursion — the three genres this change names, as one path https://stellate.app/?genre=triphop&seed=1957&path=388.8037,449.16468,945.16205&xdur=0.087

cee5ed2 https://github.com/aboard-io/stellate/commit/cee5ed2dd541d9c893b0c75734386ba9b5bc3b9e