fix(dashboard): hide "Add channel" button for users without CreateChannel permission

  Wrap the "Add channel" menu item in PermissionGuard to only show it
  to users with the CreateChannel permission.

  Fixes #4056

Author: Temporary User

packages/dashboard/src/lib/components/layout/channel-switcher.tsx

@@ -1,6 +1,7 @@
 import { ChevronsUpDown, Languages, Plus } from 'lucide-react';
 
 import { ChannelCodeLabel } from '@/vdb/components/shared/channel-code-label.js';
+import { PermissionGuard } from '@/vdb/components/shared/permission-guard.js';
 import {
     DropdownMenu,
     DropdownMenuContent,
@@ -194,17 +195,19 @@ export function ChannelSwitcher() {
                                         orderedChannels.length > 1 && <DropdownMenuSeparator />}
                                 </div>
                             ))}
-                            <DropdownMenuSeparator />
-                            <DropdownMenuItem className="gap-2 p-2 cursor-pointer" asChild>
-                                <Link to={'/channels/new'}>
-                                    <div className="bg-background flex size-6 items-center justify-center rounded-md border">
-                                        <Plus className="size-4" />
-                                    </div>
-                                    <div className="text-muted-foreground font-medium">
-                                        <Trans>Add channel</Trans>
-                                    </div>
-                                </Link>
-                            </DropdownMenuItem>
+                            <PermissionGuard requires={['CreateChannel']}>
+                                <DropdownMenuSeparator />
+                                <DropdownMenuItem className="gap-2 p-2 cursor-pointer" asChild>
+                                    <Link to={'/channels/new'}>
+                                        <div className="bg-background flex size-6 items-center justify-center rounded-md border">
+                                            <Plus className="size-4" />
+                                        </div>
+                                        <div className="text-muted-foreground font-medium">
+                                            <Trans>Add channel</Trans>
+                                        </div>
+                                    </Link>
+                                </DropdownMenuItem>
+                            </PermissionGuard>
                         </DropdownMenuContent>
                     </DropdownMenu>
                 </SidebarMenuItem>