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/features/settings/general/General.tsx

@@ -805,6 +805,80 @@ function Editor() {
 }
 
 
+function Calls() {
+  const [cameraOnJoin, setCameraOnJoin] = useSetting(settingsAtom, 'cameraOnJoin');
+  const [callNoiseSuppression, setCallNoiseSuppression] = useSetting(settingsAtom, 'callNoiseSuppression');
+  const [pttMode, setPttMode] = useSetting(settingsAtom, 'pttMode');
+  const [pttKey, setPttKey] = useSetting(settingsAtom, 'pttKey');
+  const [listeningForKey, setListeningForKey] = useState(false);
+
+  const handleKeyBind = () => {
+    setListeningForKey(true);
+    const onKey = (e: KeyboardEvent) => {
+      e.preventDefault();
+      if (e.code === 'Escape') {
+        setListeningForKey(false);
+      } else {
+        setPttKey(e.code);
+        setListeningForKey(false);
+      }
+      window.removeEventListener('keydown', onKey, true);
+    };
+    window.addEventListener('keydown', onKey, true);
+  };
+
+  const keyLabel = (code: string) => code === 'Space' ? 'Space' : code.replace('Key', '').replace('Digit', '');
+
+  return (
+    <Box direction="Column" gap="100">
+      <Text size="L400">Calls</Text>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+        <SettingTile
+          title="Join with Camera On"
+          description="Enable camera automatically when joining a voice or video call. Camera is off by default."
+          after={<Switch variant="Primary" value={cameraOnJoin} onChange={setCameraOnJoin} />}
+        />
+      </SequenceCard>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column">
+        <SettingTile
+          title="Noise Suppression"
+          description="Apply AI noise suppression to filter background noise during calls (powered by Element Call)."
+          after={<Switch variant="Primary" value={callNoiseSuppression} onChange={setCallNoiseSuppression} />}
+        />
+      </SequenceCard>
+      <SequenceCard className={SequenceCardStyle} variant="SurfaceVariant" direction="Column" gap="400">
+        <SettingTile
+          title="Push to Talk"
+          description="Mute your microphone by default. Hold the PTT key to speak."
+          after={<Switch variant="Primary" value={pttMode} onChange={setPttMode} />}
+        />
+        {pttMode && (
+          <SettingTile
+            title="PTT Key Binding"
+            description="Press a key to bind it as your push-to-talk key."
+            after={
+              <Button
+                size="300"
+                variant={listeningForKey ? 'Warning' : 'Secondary'}
+                fill={listeningForKey ? 'Solid' : 'Soft'}
+                radii="300"
+                outlined
+                onClick={handleKeyBind}
+                style={{ minWidth: '90px' }}
+              >
+                <Text size="B300">
+                  {listeningForKey ? 'Press a key…' : keyLabel(pttKey)}
+                </Text>
+              </Button>
+            }
+          />
+        )}
+      </SequenceCard>
+    </Box>
+  );
+}
+
+
 function ChatBgGrid() {
   const [chatBackground, setChatBackground] = useSetting(settingsAtom, 'chatBackground');
   const theme = useTheme();
@@ -1110,6 +1184,7 @@ export function General({ requestClose }: GeneralProps) {
               <DateAndTime />
               <Editor />
               <Messages />
+              <Calls />
             </Box>
           </PageContent>
         </Scroll>