refactor(frontend): Simplify filter bar UI and remove advanced filters popover.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/routes/__root.tsx

@@ -34,9 +34,9 @@ function RootLayout() {
         />
       )}
 
-      <div className="flex flex-col flex-1">
+      <div className="flex flex-col flex-1 min-w-0">
         <Header setSidebarOpen={setSidebarOpen} />
-        <main className="flex-1 p-6">
+        <main className="flex-1 p-6 min-w-0">
           <Outlet />
         </main>
       </div>