fix: VideoButton disabled state, PTT listener leak, TS prop errors

- VideoButton now accepts disabled prop with tooltip and visual feedback;
  PrescreenControls passes disabled=true when cameraOnJoin=false
- PTT key listener in settings tracked via ref, cleaned up on unmount,
  guarded against stacking on double-click; useCallback + useRef
- CallControls screenshare cancel button: variant Surface -> Secondary
- General.tsx Box align prop: align -> alignItems (TS2322 fix)

src/app/features/settings/general/General.tsx

@@ -3,7 +3,9 @@ import React, {
   FormEventHandler,
   KeyboardEventHandler,
   MouseEventHandler,
+  useCallback,
   useEffect,
+  useRef,
   useState,
 } from 'react';
 import dayjs from 'dayjs';
@@ -378,7 +380,7 @@ function Appearance() {
           title="Lotus Terminal Mode"
           description="LotusGuild Terminal Design System: Anduril Orange + Ice Cyan + Matrix Green, dot-grid background, CRT scanlines, and boot sequence animation."
           after={
-            <Box direction="Row" gap="200" align="Center">
+            <Box direction="Row" gap="200" alignItems="Center">
               {lotusTerminal && (
                 <button
                   type="button"
@@ -811,8 +813,18 @@ function Calls() {
   const [pttMode, setPttMode] = useSetting(settingsAtom, 'pttMode');
   const [pttKey, setPttKey] = useSetting(settingsAtom, 'pttKey');
   const [listeningForKey, setListeningForKey] = useState(false);
+  const keyListenerRef = useRef<((e: KeyboardEvent) => void) | null>(null);
 
-  const handleKeyBind = () => {
+  useEffect(
+    () => () => {
+      if (keyListenerRef.current)
+        window.removeEventListener('keydown', keyListenerRef.current, true);
+    },
+    []
+  );
+
+  const handleKeyBind = useCallback(() => {
+    if (listeningForKey) return;
     setListeningForKey(true);
     const onKey = (e: KeyboardEvent) => {
       e.preventDefault();
@@ -823,9 +835,11 @@ function Calls() {
         setListeningForKey(false);
       }
       window.removeEventListener('keydown', onKey, true);
+      keyListenerRef.current = null;
     };
+    keyListenerRef.current = onKey;
     window.addEventListener('keydown', onKey, true);
-  };
+  }, [listeningForKey, setPttKey]);
 
   const keyLabel = (code: string) => code === 'Space' ? 'Space' : code.replace('Key', '').replace('Digit', '');