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/call/CallControls.tsx

@@ -1,4 +1,4 @@
-import React, { MouseEventHandler, useCallback, useRef, useState } from 'react';
+import React, { MouseEventHandler, useCallback, useEffect, useRef, useState } from 'react';
 import {
   Box,
   Button,
@@ -26,6 +26,8 @@ import {
   VideoButton,
 } from './Controls';
 import { CallEmbed, useCallControlState } from '../../plugins/call';
+import { useSetting } from '../../state/hooks/settings';
+import { settingsAtom } from '../../state/settings';
 import { useResizeObserver } from '../../hooks/useResizeObserver';
 import { stopPropagation } from '../../utils/keyboard';
 import { AsyncStatus, useAsyncCallback } from '../../hooks/useAsyncCallback';
@@ -51,6 +53,10 @@ export function CallControls({ callEmbed }: CallControlsProps) {
   );
 
   const [cords, setCords] = useState<RectCords>();
+  const [shareConfirm, setShareConfirm] = useState(false);
+  const [pttMode] = useSetting(settingsAtom, 'pttMode');
+  const [pttKey] = useSetting(settingsAtom, 'pttKey');
+  const [pttActive, setPttActive] = useState(false);
 
   const handleOpenMenu: MouseEventHandler<HTMLButtonElement> = (evt) => {
     setCords(evt.currentTarget.getBoundingClientRect());
@@ -71,12 +77,37 @@ export function CallControls({ callEmbed }: CallControlsProps) {
     setCords(undefined);
   };
 
+  useEffect(() => {
+    if (!pttMode) return;
+    const onKeyDown = (e: KeyboardEvent) => {
+      if (e.code === pttKey && !e.repeat && !microphone) {
+        e.preventDefault();
+        callEmbed.control.setMicrophone(true);
+        setPttActive(true);
+      }
+    };
+    const onKeyUp = (e: KeyboardEvent) => {
+      if (e.code === pttKey) {
+        callEmbed.control.setMicrophone(false);
+        setPttActive(false);
+      }
+    };
+    window.addEventListener('keydown', onKeyDown);
+    window.addEventListener('keyup', onKeyUp);
+    return () => {
+      window.removeEventListener('keydown', onKeyDown);
+      window.removeEventListener('keyup', onKeyUp);
+    };
+  }, [pttMode, pttKey, callEmbed, microphone]);
+
   const [hangupState, hangup] = useAsyncCallback(
     useCallback(() => callEmbed.hangup(), [callEmbed])
   );
   const exiting =
     hangupState.status === AsyncStatus.Loading || hangupState.status === AsyncStatus.Success;
 
+  const pttKeyLabel = pttKey === 'Space' ? 'SPACE' : pttKey.replace('Key', '').replace('Digit', '');
+
   return (
     <Box
       ref={controlRef}
@@ -84,6 +115,63 @@ export function CallControls({ callEmbed }: CallControlsProps) {
       justifyContent="Center"
       alignItems="Center"
     >
+      {pttMode && (
+        <Box
+          style={{
+            position: 'absolute',
+            top: '-2.5rem',
+            left: '50%',
+            transform: 'translateX(-50%)',
+            background: pttActive ? 'rgba(0,255,136,0.18)' : 'rgba(255,107,0,0.12)',
+            border: `1px solid ${pttActive ? 'rgba(0,255,136,0.55)' : 'rgba(255,107,0,0.35)'}`,
+            borderRadius: '99px',
+            padding: '0.2rem 0.9rem',
+            pointerEvents: 'none',
+            whiteSpace: 'nowrap',
+          }}
+        >
+          <Text size="T200" style={{ color: pttActive ? '#00FF88' : '#FF6B00', fontWeight: 700, letterSpacing: '0.08em' }}>
+            {pttActive ? '● LIVE' : `PTT — Hold ${pttKeyLabel}`}
+          </Text>
+        </Box>
+      )}
+      {shareConfirm && (
+        <Box
+          style={{
+            position: 'absolute',
+            bottom: '110%',
+            left: '50%',
+            transform: 'translateX(-50%)',
+            background: 'var(--bg-surface)',
+            border: '1px solid var(--border-color)',
+            borderRadius: '0.75rem',
+            padding: '1rem 1.25rem',
+            zIndex: 100,
+            minWidth: '260px',
+            boxShadow: '0 8px 32px rgba(0,0,0,0.35)',
+            display: 'flex',
+            flexDirection: 'column',
+            gap: '0.75rem',
+          }}
+        >
+          <Text size="T300" style={{ fontWeight: 600 }}>Share your screen?</Text>
+          <Text size="T200" style={{ opacity: 0.75 }}>Your screen will be visible to all participants in this call.</Text>
+          <Box gap="200">
+            <Button
+              size="300" variant="Success" fill="Solid" radii="300"
+              onClick={() => { callEmbed.control.toggleScreenshare(); setShareConfirm(false); }}
+            >
+              <Text size="B300">Share</Text>
+            </Button>
+            <Button
+              size="300" variant="Surface" fill="Soft" radii="300" outlined
+              onClick={() => setShareConfirm(false)}
+            >
+              <Text size="B300">Cancel</Text>
+            </Button>
+          </Box>
+        </Box>
+      )}
       <SequenceCard
         className={css.ControlCard}
         variant="SurfaceVariant"
@@ -105,7 +193,10 @@ export function CallControls({ callEmbed }: CallControlsProps) {
             <VideoButton enabled={video} onToggle={() => callEmbed.control.toggleVideo()} />
             <ScreenShareButton
               enabled={screenshare}
-              onToggle={() => callEmbed.control.toggleScreenshare()}
+              onToggle={() => screenshare
+                ? callEmbed.control.toggleScreenshare()
+                : setShareConfirm(true)
+              }
             />
           </Box>
         </Box>