refactor(fe): replace TanStack Query with SWR + UI/data cleanup

Rombak data layer frontend:
- Hapus @tanstack/react-query (package.json, lockfile, provider di
  dashboard layout) — ganti SWR 2.4.2 + SWRConfig (revalidateOnFocus
  false, deduping 10s, no retry on 404)
- Semua hooks data ditulis ulang ke useSWR; useAction() helper baru
  pengganti useMutation dengan surface kompatibel (mutate/mutateAsync/
  isPending/error)
- useMessages + useMessagesHasMore share satu SWR key — probe cursor
  yang tadinya dobel fetch API sekarang deduped
- WS sync (messages/media/recordings) pindah dari queryClient ke
  SWR mutate dengan filter key + revalidate:false
- useMessageSearch() dipakai search-panel & search-overlay; search
  overlay backdrop div -> button (fix a11y lint)

Rapikan UI + isi data:
- Tab stats recordings: placeholder 'coming soon' diganti stat asli
  (total, ukuran, speaker unik, top speakers)
- Empty states konsisten via EmptyState (images/review/recordings),
  EmptyState terima className
- biome check --write: 0 error, 8 warning pre-existing
- Verifikasi: tsc --noEmit PASS, next build PASS (11 halaman static),
  API live dicek — semua endpoint dashboard/messages/guilds/config/
  voice/media/recordings/review balikin data

services/frontend/src/app/(dashboard)/layout.tsx

@@ -1,25 +1,18 @@
 "use client";
 
-import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import { Suspense, useEffect, useState } from "react";
-import { TopNav } from "@/components/layout/top-nav";
-import { MobileNav } from "@/components/layout/mobile-nav";
-import { WsProvider, useWebSocket } from "@/lib/ws/context";
-import { ChatbotProvider, useChatbot } from "@/components/chatbot/chatbot-context";
+import { SWRConfig } from "swr";
 import { ChatbotContainer } from "@/components/chatbot/chatbot-container";
+import {
+  ChatbotProvider,
+  useChatbot,
+} from "@/components/chatbot/chatbot-context";
+import { HiddenSidebar } from "@/components/layout/hidden-sidebar";
+import { MobileNav } from "@/components/layout/mobile-nav";
+import { TopNav } from "@/components/layout/top-nav";
 import { MiniPlayer } from "@/components/media/mini-player";
 import { MediaPlayerProvider } from "@/lib/hooks/use-media-player";
-import { HiddenSidebar } from "@/components/layout/hidden-sidebar";
-
-const queryClient = new QueryClient({
-  defaultOptions: {
-    queries: {
-      staleTime: 10_000,
-      retry: 1,
-      refetchOnWindowFocus: false,
-    },
-  },
-});
+import { useWebSocket, WsProvider } from "@/lib/ws/context";
 
 function ChatbotExpressionSync() {
   const ws = useWebSocket();
@@ -54,14 +47,24 @@ export default function DashboardLayout({
   const [guildId, setGuildId] = useState("");
 
   return (
-    <QueryClientProvider client={queryClient}>
+    <SWRConfig
+      value={{
+        revalidateOnFocus: false,
+        dedupingInterval: 10_000,
+        shouldRetryOnError: (err) =>
+          (err as { statusCode?: number })?.statusCode !== 404,
+      }}
+    >
       <WsProvider>
         <MediaPlayerProvider>
           <ChatbotProvider>
             <ChatbotExpressionSync />
             <div className="min-h-screen bg-canvas">
               <TopNav />
-              <HiddenSidebar guildId={guildId} onGuildChange={(g) => setGuildId(g ?? "")} />
+              <HiddenSidebar
+                guildId={guildId}
+                onGuildChange={(g) => setGuildId(g ?? "")}
+              />
 
               {/* Sub-nav space — filled per-page */}
               <div className="pt-11">
@@ -85,6 +88,6 @@ export default function DashboardLayout({
           </ChatbotProvider>
         </MediaPlayerProvider>
       </WsProvider>
-    </QueryClientProvider>
+    </SWRConfig>
   );
 }