feat: add BullMQ queue infrastructure and frontend job status hook

- apps/Backend/src/queue/: connection, queues, workers, processors
- apps/Frontend/src/hooks/use-job-status.ts: WebSocket job progress hook
- apps/Frontend/src/lib/socket.ts: shared Socket.IO singleton

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/Frontend/src/lib/socket.ts

@@ -0,0 +1,24 @@
+/**
+ * Shared Socket.IO client singleton.
+ *
+ * Import `socket` anywhere in the frontend to use the shared connection.
+ * The socket connects lazily — the first import triggers the connection.
+ */
+import { io, Socket } from "socket.io-client";
+
+const SOCKET_URL =
+  import.meta.env.VITE_API_BASE_URL_BACKEND ||
+  (typeof window !== "undefined" ? window.location.origin : "");
+
+export const socket: Socket = io(SOCKET_URL, {
+  withCredentials: true,
+  autoConnect: true,
+});
+
+socket.on("connect", () => {
+  console.log("[socket] connected:", socket.id);
+});
+
+socket.on("disconnect", () => {
+  console.log("[socket] disconnected");
+});