chore(lotus): fix stale denoise flag docs + prep 0.20.1-lotus.2

The in-source ML denoiser is gated on lotusDenoiseSource (see lotusDenoise.ts
gate), not the legacy build-time shim flag lotusDenoise=ml. Correct the two
stale references (lotusDenoise.ts JSDoc + InCallView.tsx comment) to
lotusDenoiseSource=1.

Bump the embedded package to 0.20.1-lotus.2 for the next publish and update the
CI comment: the checked-in version now tracks the intended release, while a
pushed tag still wins (npm version "$TAG" overwrites at publish time).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

embedded/web/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@lotusguild/element-call-embedded",
-  "version": "0.0.0",
+  "version": "0.20.1-lotus.2",
   "files": [
     "README.md",
     "LICENSE-AGPL-3.0",