delete what is actually dead; keep what only looked dead

The audit that proposed this pass graded far too much as dead, because it grepped for test wrappers instead of the requires. Checking each claim first:

• engine/checks/ (5 files, 899 lines) — "zero CI reach". WRONG.

• tools/make-mix-page.js — "zero references". WRONG. genre-kernel.js:8942 and :8978 execFileSync it from the playlist and journey CLIs.

• tools/fetch-found-voice.sh — "dead". It is the committed recipe SOURCES.md cites as the provenance for the voice tier, which is the whole media policy: we ship the recipe, not the media.

• What was genuinely unreferenced, and is now gone (1,431 lines): seven probe-*.js with no citation anywhere, and the four starcruise screenshot scripts, which produce PNGs and assert nothing.

Verified: probe-reverb.js and friends — "unreferenced one-offs". Five .dsp source files and engine/faust/VOICES.md cite them by name as the tuning instruments for those DSPs.

▶ Play it: Neon Fiscal Year — the embeddable player, in someone else's page https://stellate.app/embed.html?genre=citypop&seed=6859&path=1530.6199,1549.6232,1511.6232&xdur=13.122

0d0fea6 https://github.com/aboard-io/stellate/commit/0d0fea6baf00b9dd23c6cb59e79daee15adeb38a