docs(call): cover soundboard/quality/permissions in user-facing docs

- README "Calls & Voice": add the in-call soundboard, per-user call quality
  settings, and admin room call-permissions bullets.
- LOTUS_TODO: mark the soundboard UI as built (was "cinny UI remains / dormant").
- HANDOFF_ELEMENT_CALL_FORK: add a COMPLETE status banner to the §12.1 host
  checklist; fix stale denoise specifics (all four models are in-source;
  flag is lotusDenoiseSource=1, not lotusDenoise=ml).

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

HANDOFF_ELEMENT_CALL_FORK.md

@@ -548,8 +548,19 @@ roster capped. Only `https`/`blob` URLs accepted for inject/decoration assets.
 
 ### 12.1 cinny host integration checklist (REQUIRED to light these up)
 
-The EC side is additive and dormant until cinny opts in. Host work needed (in
-`src/app/plugins/call/CallEmbed.ts` unless noted):
+> ✅ **STATUS (2026-06): COMPLETE.** All items below are shipped. call_state,
+> focus_participant, decorations, and transparent background are active; the
+> in-source denoise cutover is done (flag `lotusDenoiseSource=1`, **all four**
+> models in-source); and the two formerly-dormant capabilities now have cinny
+> UI — **soundboard** (`io.lotus.inject_audio`, P5-15) and **quality controls +
+> room permissions** (`io.lotus.set_quality` + `io.lotus.room_quality`, P5-31,
+> with server-side enforcement in `LotusGuild/matrix`). See `LOTUS_FEATURES.md`
+> → "Element Call — Self-Built Fork". The checklist is kept below as the record
+> of what was wired. (One open denoise item tracked separately: the "Series
+> Suppression" native-NS toggle is not wired to the real call path.)
+
+The EC side is additive and dormant until cinny opts in. Host work (in
+`src/app/plugins/call/CallEmbed.ts` unless noted) — **done**:
 
 > ⚠️ **CRITICAL TIMING (protocol audit F1):** only send `io.lotus.*` **toWidget**
 > actions (#3 focus, #6 decorations, #7 quality, audio-inject) **after** the call
@@ -559,16 +570,16 @@ The EC side is additive and dormant until cinny opts in. Host work needed (in
 > leaves the host's `transport.send` pending until the **10s timeout**. Queue and
 > flush on join, or no-op before join.
 >
-> Also: **F3** — the fork implements only `rnnoise`/`speex`; cinny's `dtln`/
-> `deepfilternet` selections silently fall back to rnnoise (now logged). Restrict
-> the embedded-call model picker to rnnoise/speex, or implement the others in
-> `lotusDenoiseProcessor.ts`. **F4** — cinny sends `lotusNativeNS`, which the
-> fork ignores; drop it or wire it in. **F7** — no widget _capability_ changes
-> needed; custom actions bypass capability checks.
+> Also: **F3 (RESOLVED)** — all four models (`rnnoise`/`speex`/`dtln`/
+> `deepfilternet`) are now implemented in-source in `lotusDenoiseProcessor.ts`;
+> the picker offers all four. **F4** — cinny no longer forwards a native-NS flag
+> in the `ml` branch (the "Series Suppression" toggle is currently a no-op in
+> real calls — open item). **F7** — no widget _capability_ changes needed;
+> custom actions bypass capability checks.
 
 1. **Set the URL flags** on the widget iframe params (the `URLSearchParams` in
    `CallEmbed`): `lotusCallState=1`, `lotusTransparent=1`/`lotusTheme=1`,
-   `lotusAudioInject=1` as desired. (Denoise already sets `lotusDenoise=ml` etc.)
+   `lotusAudioInject=1` as desired. (Denoise sets `lotusDenoiseSource=1` + `lotusModel`/`lotusGate`/`lotusGateThreshold` in the `ml` tier.)
 2. **Ack `io.lotus.call_state`**: add `listenAction('io.lotus.call_state', …)` —
    without a reply the fork's sends time out every 250ms. Feed the payload into
    `useCallSpeakers` and RETIRE its `contentDocument` DOM scrape.