feat(call): in-call soundboard, quality controls, room call-permissions

Element Call is now consumed as our self-built fork
(@lotusguild/element-call-embedded); wire up its previously-dormant
capabilities and document the fork as live.

Soundboard (P5-15): a call-bar button plays user-uploaded audio clips into the
call as a real published track (io.lotus.inject_audio) plus local playback.
Clips are uploadable like emoji/sticker packs, stored in io.lotus.soundboard
account data (synced across devices). Gated by a Settings toggle + volume.

Quality controls (P5-31): per-user mic/screenshare bitrate + screenshare
framerate (Settings -> Calls), applied via io.lotus.set_quality clamped to any
room cap. Room admins set caps and hard call-permissions (allow_screenshare /
allow_camera) in Room Settings -> Voice; the call bar hides blocked buttons.

- New: CallSoundboard, useSoundboard, soundboardClips; RoomQuality,
  useCallQuality, callQuality (+ unit tests).
- Optimistic-write RoomQuality admin UI (no stale-state clobber).
- Docs: mark EC fork live across README/FEATURES/TODO/BUGS/TESTING; add D2
  manual-test steps.

Numeric quality caps are client-cooperative; screenshare/camera permissions are
hard-enforced server-side (see LotusGuild/matrix voice-limit-guard).

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

README.md

@@ -144,22 +144,25 @@ The source code lives in `/root/code/cinny`. All changes should be made on the `
 
 See [LOTUS_FEATURES.md](LOTUS_FEATURES.md) for the full feature changelog and [LOTUS_TODO.md](LOTUS_TODO.md) for the work backlog.
 
-### 🔱 Planned: Element Call fork ("Lotus Call")
+### 🔱 Element Call fork ("Lotus Call") — LIVE
 
-Voice/video channels embed **Element Call**. Today it's a **pre-built npm bundle**
-(`@element-hq/element-call-embedded` 0.20.1) copied to `public/element-call/` and
-served same-origin; we steer it via the `matrix-widget-api` plus fragile DOM
-hacks. Because we don't own its compiled source, several in-call issues (avatar
-decorations on tiles, camera focus/fullscreen during screenshare, mic recovery
-after reconnect, native theming, real call-audio injection) are unfixable from
-outside.
+Voice/video channels embed **Element Call**, which is now our **self-built fork**
+(`@lotusguild/element-call-embedded` `0.20.1-lotus.1`, source at
+`LotusGuild/element-call`), published to our private Gitea npm registry and served
+same-origin. We no longer depend on the upstream prebuilt bundle, so in-call
+behavior is editable source instead of fragile DOM/widget hacks.
 
-**The plan is to fork `element-hq/element-call` into a new `LotusGuild/element-call`
-repo, build it from source, and host our own build** for true ownership. The full
-self-contained plan and integration map — written for a fresh session with no
-prior context — is in **[`HANDOFF_ELEMENT_CALL_FORK.md`](HANDOFF_ELEMENT_CALL_FORK.md)**.
-Infra/hosting notes also live in the `LotusGuild/matrix` repo README. Search the
-docs for the **`[EC-FORK]`** tag to find every related note.
+**Shipped via the fork:** denoise as an in-source LiveKit audio stage (survives
+reconnects), in-call speaking/mute events, focus-a-participant during screenshare,
+avatar decorations on EC video tiles, and a native transparent background.
+**Built but dormant (need cinny UI):** real call-audio injection
+(`io.lotus.inject_audio` → in-call soundboard) and quality controls
+(`io.lotus.set_quality`).
+
+The full plan and integration map is in
+**[`HANDOFF_ELEMENT_CALL_FORK.md`](HANDOFF_ELEMENT_CALL_FORK.md)**; infra/hosting +
+build-pipeline notes live in the `LotusGuild/matrix` repo README. Search the docs
+for the **`[EC-FORK]`** tag to find every related note.
 
 ### Build