perf(frontend,config): parallelize auth, virtualize logs, cache public configs

Frontend layout renders immediately; pages gate via RequireAuth and
useAuthRedirect. Login/register skip getUserInfo. Admin log panel uses
useVirtualizer to avoid 2000-row DOM. ListVisibleSystemConfigs caches
visibility=1 configs in Redis with invalidation on create/update.
PERFORMANCE.md marks completed optimizations.

frontend/hooks/use-auth-redirect.ts

@@ -0,0 +1,27 @@
+"use client"
+
+import {useEffect} from "react"
+import {usePathname, useRouter} from "next/navigation"
+
+import {useUser} from "@/contexts/user-context"
+
+/** Redirects unauthenticated users to login while allowing the shell to render first. */
+export function useAuthRedirect() {
+  const router = useRouter()
+  const pathname = usePathname()
+  const {user, loading} = useUser()
+
+  useEffect(() => {
+    if (loading || user) {
+      return
+    }
+
+    const queryString = window.location.search
+    const callbackUrl = queryString ? `${pathname}${queryString}` : pathname
+    const loginUrl = new URL("/login", window.location.origin)
+
+    loginUrl.searchParams.set("callbackUrl", callbackUrl)
+    sessionStorage.setItem("redirect_after_login", callbackUrl)
+    router.replace(loginUrl.toString())
+  }, [loading, pathname, router, user])
+}