fix: deduplicate VolumeSliderItem and add missing stopPropagation

- Extract VolumeSliderItem to voiceMenuItems.tsx (was duplicated in
  VoiceUser.tsx and VoiceChannel.tsx)
- Add e.stopPropagation() to all imperative context menu handlers
  for consistency with useContextMenu hook behavior

packages/web/src/components/voice/VoiceUser.tsx

@@ -2,7 +2,7 @@ import React, { useRef, useEffect, useState, useCallback } from 'react';
 import { Avatar } from '../ui/Avatar';
 import { useVoiceStore } from '../../stores/voiceStore';
 import { useContextMenuStore, type ContextMenuItem } from '../../stores/contextMenuStore';
-import { buildVoiceModMenuItems } from './voiceMenuItems';
+import { buildVoiceModMenuItems, VolumeSliderItem } from './voiceMenuItems';
 import { useSpaceStore } from '../../stores/spaceStore';
 import { useVoiceParticipantMeta } from '../../hooks/useVoiceParticipantMeta';
 import { getActiveRoom, setCameraSubscription } from '../../hooks/useLiveKit';
@@ -13,36 +13,6 @@ interface VoiceUserProps {
   large?: boolean;
 }
 
-/** Wrapper component for the volume slider so it can use hooks (useState). */
-function VolumeSliderItem({ userId }: { userId: string }) {
-  const volume = useVoiceStore((s) => s.participantVolumes.get(userId) ?? 100);
-  const setParticipantVolume = useVoiceStore((s) => s.setParticipantVolume);
-
-  return (
-    <div className="p-3">
-      <div className="text-xs text-txt-tertiary mb-2 font-medium uppercase tracking-wider">
-        User Volume
-      </div>
-      <div className="flex items-center gap-2">
-        <svg width="16" height="16" viewBox="0 0 24 24" fill="currentColor" className="text-txt-tertiary flex-shrink-0">
-          <path d="M3 9v6h4l5 5V4L7 9H3z" />
-        </svg>
-        <input
-          type="range"
-          min="0"
-          max="200"
-          value={volume}
-          onChange={(e) => setParticipantVolume(userId, parseInt(e.target.value))}
-          className="flex-1 accent-accent-primary h-1"
-        />
-        <span className="text-xs text-txt-secondary min-w-[32px] text-right">
-          {volume}%
-        </span>
-      </div>
-    </div>
-  );
-}
-
 export function VoiceUser({ tile, large }: VoiceUserProps) {
   const videoRef = useRef<HTMLVideoElement>(null);
 
@@ -97,6 +67,7 @@ export function VoiceUser({ tile, large }: VoiceUserProps) {
     (e: React.MouseEvent) => {
       if (isLocal || !currentVoiceChannelId) return;
       e.preventDefault();
+      e.stopPropagation();
 
       const targetUserId = participant.userId;
       const channelId = currentVoiceChannelId;