docs(call): document soundboard/quality/permissions (README table + landing)

- README Custom Features table: add rows for the in-call soundboard (P5-15),
  call quality controls, and room call-permissions (P5-31).
- landing: mention the soundboard, per-user quality controls, and
  server-enforced room call-permissions in the feature blurb.

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

README.md

@@ -502,6 +502,9 @@ All custom code lives in `src/app/` on the `lotus` branch of `code.lotusguild.or
 | **Screenshare fullscreen** | `src/app/features/call/CallControls.tsx`, `src/app/features/call/Controls.tsx` | When screensharing, a fullscreen button appears in call controls. Calls `callEmbedRef.current?.requestFullscreen()` on the Cinny call container. EC naturally spotlights the screenshare — the old 600ms grid-revert code was removed (it caused fullscreen to show avatars instead of the screen) |
 | **PiP screenshare focus** | `src/app/components/CallEmbedProvider.tsx`, `src/app/plugins/call/CallControl.ts` | When the floating PiP window is active and screenshare is detected (no cameras present), auto-enables EC spotlight view so the screenshare fills the PiP rather than showing avatar tiles |
 | **Screenshare audio mute** | `src/app/features/call/Controls.tsx`, `src/app/features/call/CallControls.tsx`, `src/app/plugins/call/CallControl.ts` | Dedicated button to independently mute/unmute audio from screenshares without muting microphone audio. Targets `audio[data-lk-source="screen_share_audio"]` LiveKit elements. Persists across deafen/undeafen cycles |
+| **In-call soundboard (P5-15)** | `src/app/features/call/CallSoundboard.tsx`, `src/app/hooks/useSoundboard.ts`, `src/app/utils/soundboardClips.ts`, `CallControl.ts#injectAudio` | Call-bar popout of user-uploaded clips. Playing one sends the fork's `io.lotus.inject_audio` (armed via `lotusAudioInject=1`) so it publishes as a real LiveKit track heard by all, plus local playback. Clips are uploadable like emoji/sticker packs — stored in `io.lotus.soundboard` account data (synced across devices); host resolves mxc → authed download → `blob:` URL for the widget. Gated by `soundboardEnabled` setting |
+| **Call quality controls (P5-31)** | `src/app/utils/callQuality.ts`, `src/app/hooks/useCallQuality.ts`, `CallControl.ts#setQuality` | Per-user mic/screenshare bitrate + screenshare framerate (Settings → Calls), applied via the fork's `io.lotus.set_quality`, clamped to any room cap (`min(user, room)`). **Client-cooperative** (numeric caps aren't SFU-enforceable). Unit-tested |
+| **Room call permissions (P5-31)** | `src/app/features/common-settings/general/RoomQuality.tsx`, `types/matrix/room.ts` (`LotusRoomQuality`), `CallControls.tsx` | Admin switches in Room Settings → Voice write `io.lotus.room_quality` `allow_screenshare`/`allow_camera`; the call bar hides blocked buttons. **Hard-enforced server-side for all clients** by `voice-limit-guard` (this repo) — see [Voice Channel Limits & Call Permissions](#voice-channel-limits--call-permissions) |
 | **Custom status message** | `src/app/features/settings/account/Profile.tsx`, `src/app/features/room/MembersDrawer.tsx`, `src/app/components/user-profile/UserHero.tsx`, `src/app/components/user-profile/UserRoomProfile.tsx`, `src/app/hooks/useUserPresence.ts` | Discord-style free-form status text. Set via Settings → Account → "Status Message" with an emoji picker (lazy-loaded `EmojiBoard`). Saved via `mx.setPresence({ status_msg })`. Displayed below the username in the members drawer and user profile popout. Syncs live via Matrix presence events |
 | **PTT (Push-to-Talk)** | `src/app/features/call/CallControls.tsx`, `src/app/state/settings.ts` | Hold-to-talk key (default: Space, configurable). Mutes mic on join; holds mic open while key is held. Badge shows `PTT — Hold SPACE` / `● Live`. Listens on both main window and EC iframe `contentWindow` for key events |
 | **PTT badge theming** | `src/app/features/call/CallControls.tsx` | Plain folds `Chip` by default; neon terminal style (`#00FF88`/`#FF6B00`, JetBrains Mono) when `lotusTerminal` setting is on |