feat(calls): 3-tier mic noise suppression with on-device ML (P5-30)

Replace the boolean call noise-suppression setting with a 3-way control
(Off / Browser-native / ML beta) in Settings -> General -> Calls.

- Off: noiseSuppression=false to Element Call
- Browser-native: EC's built-in WebRTC suppressor (prior default)
- ML (beta): on-device RNNoise (@sapphi-red/web-noise-suppressor)

Element Call captures the mic inside its iframe and publishes to LiveKit,
so the host can't reach that track; LiveKit's Krisp filter is Cloud-only
(we self-host the SFU) and EC's own RNNoise PR #3892 is unmerged. The ML
tier instead injects a same-origin pre-init shim into the vendored EC
index.html (build/lotus-denoise.js, wired by the lotusDenoise vite plugin)
that patches getUserMedia and routes the captured mic through an RNNoise
AudioWorklet before LiveKit sees it -- the same post-capture pipeline as
#3892, with no EC fork/AGPL/rebase burden. Falls back to the raw mic if
setup fails; keeps echoCancellation/AGC on the raw capture.

- settings.ts: callNoiseSuppression -> 'off'|'browser'|'ml' + legacy
  boolean migration (true->browser, false->off)
- CallEmbed/useCallEmbed: tier maps to noiseSuppression param and appends
  lotusDenoise=ml (native suppressor off in ML mode)
- vite.config.js: copy RNNoise worklet/wasm + shim into the EC bundle and
  inject the shim <script> before EC's module entry
- docs: LOTUS_FEATURES.md, LOTUS_TODO.md (P5-30 done)

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

package.json

@@ -44,6 +44,7 @@
     "@giphy/js-types": "5.1.0",
     "@giphy/js-util": "5.2.0",
     "@giphy/react-components": "10.1.2",
+    "@sapphi-red/web-noise-suppressor": "0.3.5",
     "@sentry/react": "10.53.1",
     "@tanstack/react-query": "5.100.13",
     "@tanstack/react-query-devtools": "5.100.13",