Add omarchy-audio-tuner

Tools for authoring the per-model speaker tunings Omarchy ships. Split out of the
Omarchy tree because measuring a laptop and fitting a filter-chain is contributor
work almost nobody does, and it needs python, ffmpeg and mpv, none of which
Omarchy installs.

Depends on lsp-plugins-lv2 as well, since that supplies the lookahead limiter a
generated chain ends in and is needed to audition the result, not only author it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkgbuilds/omarchy-audio-tuner/.omarchy/package.json

@@ -0,0 +1,3 @@
+{
+  "source": "local"
+}