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>

src/app/hooks/useCallEmbed.ts

@@ -15,7 +15,7 @@ import { CallControlState } from '../plugins/call/CallControlState';
 import { useCallMembersChange, useCallSession } from './useCall';
 import { CallPreferences } from '../state/callPreferences';
 import { useSetting } from '../state/hooks/settings';
-import { settingsAtom } from '../state/settings';
+import { NoiseSuppressionMode, settingsAtom } from '../state/settings';
 import { unlockCallSounds } from '../utils/callSounds';
 
 const CallEmbedContext = createContext<CallEmbed | undefined>(undefined);
@@ -45,7 +45,7 @@ export const createCallEmbed = (
   themeKind: ElementCallThemeKind,
   container: HTMLElement,
   pref?: CallPreferences,
-  noiseSuppression = true,
+  denoiseMode: NoiseSuppressionMode = 'browser',
   forceAudioOff = false,
 ): CallEmbed => {
   const rtcSession = mx.matrixRTC.getRoomSession(room);
@@ -59,7 +59,7 @@ export const createCallEmbed = (
     room,
     intent,
     themeKind,
-    noiseSuppression,
+    denoiseMode,
     initialAudio,
     initialVideo,
   );
@@ -96,7 +96,7 @@ export const useCallStart = (dm = false) => {
         theme.kind,
         container,
         pref,
-        callNoiseSuppression ?? true,
+        callNoiseSuppression ?? 'browser',
         !!pttMode,
       );