feat(call): PTT, deafen label, camera default off, screenshare confirm, noise suppression setting

- Push to Talk: keydown/keyup binds mic to configurable key (default Space)
  with visual PTT indicator and key-binding UI in Settings > General > Calls
- Camera always defaults OFF on join; cameraOnJoin setting for explicit opt-in
- Deafen button tooltip corrected to Deafen/Undeafen instead of Turn Off/On Sound
- Screenshare confirmation dialog before broadcasting to call participants
- Noise suppression toggle wired from settings through CallEmbed URL params
- CallControl.setMicrophone() public method for programmatic mic control
- Calls settings section added to General settings page

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/hooks/useCallEmbed.ts

@@ -15,6 +15,8 @@ import { useResizeObserver } from './useResizeObserver';
 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';
 
 const CallEmbedContext = createContext<CallEmbed | undefined>(undefined);
 
@@ -42,14 +44,15 @@ export const createCallEmbed = (
   dm: boolean,
   themeKind: ElementCallThemeKind,
   container: HTMLElement,
-  pref?: CallPreferences
+  pref?: CallPreferences,
+  noiseSuppression = true
 ): CallEmbed => {
   const rtcSession = mx.matrixRTC.getRoomSession(room);
   const ongoing =
     MatrixRTCSession.sessionMembershipsForRoom(room, rtcSession.sessionDescription).length > 0;
 
   const intent = CallEmbed.getIntent(dm, ongoing);
-  const widget = CallEmbed.getWidget(mx, room, intent, themeKind);
+  const widget = CallEmbed.getWidget(mx, room, intent, themeKind, noiseSuppression);
   const controlState = pref && new CallControlState(pref.microphone, pref.video, pref.sound);
 
   const embed = new CallEmbed(mx, room, widget, container, controlState);
@@ -62,6 +65,7 @@ export const useCallStart = (dm = false) => {
   const theme = useTheme();
   const setCallEmbed = useSetAtom(callEmbedAtom);
   const callEmbedRef = useCallEmbedRef();
+  const [callNoiseSuppression] = useSetting(settingsAtom, 'callNoiseSuppression');
 
   const startCall = useCallback(
     (room: Room, pref?: CallPreferences) => {
@@ -69,11 +73,11 @@ export const useCallStart = (dm = false) => {
       if (!container) {
         throw new Error('Failed to start call, No embed container element found!');
       }
-      const callEmbed = createCallEmbed(mx, room, dm, theme.kind, container, pref);
+      const callEmbed = createCallEmbed(mx, room, dm, theme.kind, container, pref, callNoiseSuppression ?? true);
 
       setCallEmbed(callEmbed);
     },
-    [mx, dm, theme, setCallEmbed, callEmbedRef]
+    [mx, dm, theme, setCallEmbed, callEmbedRef, callNoiseSuppression]
   );
 
   return startCall;