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>

src/types/matrix/accountData.ts

@@ -10,6 +10,10 @@ export enum AccountDataEvent {
   PoniesUserEmotes = 'im.ponies.user_emotes',
   PoniesEmoteRooms = 'im.ponies.emote_rooms',
 
+  // [P5-15] Personal, uploadable in-call soundboard clips (synced across
+  // devices like custom emoji/sticker packs).
+  LotusSoundboard = 'io.lotus.soundboard',
+
   SecretStorageDefaultKey = 'm.secret_storage.default_key',
 
   CrossSigningMaster = 'm.cross_signing.master',

src/types/matrix/room.ts

@@ -41,6 +41,7 @@ export enum StateEvent {
   PoniesRoomEmotes = 'im.ponies.room_emotes',
   PowerLevelTags = 'in.cinny.room.power_level_tags',
   LotusVoiceLimit = 'io.lotus.voice_limit',
+  LotusRoomQuality = 'io.lotus.room_quality',
 }
 
 export enum MessageEvent {