Remove unused button from Topbar for a cleaner interface

src/components/layout/Topbar.tsx

@@ -35,20 +35,6 @@ export function Topbar() {
           </TooltipTrigger>
           <TooltipContent side="bottom">通知</TooltipContent>
         </Tooltip>
-
-        <button className="flex items-center gap-2.5 rounded-full border border-hairline-strong px-3 py-1.5 transition-colors hover:bg-surface-strong">
-          <div
-            className="flex h-8 w-8 items-center justify-center rounded-full text-sm font-medium text-on-primary"
-            style={{
-              backgroundColor: "var(--primary)",
-              backgroundImage:
-                "radial-gradient(circle at 30% 20%, color-mix(in srgb, var(--gradient-sky) 70%, transparent), transparent 60%)",
-              color: "var(--primary-foreground)",
-            }}
-          >
-            A
-          </div>
-        </button>
       </TooltipProvider>
     </header>
   );