feat: migrate frontend to Astro SSG with design system

- Replace monolithic React SPA (App.tsx) with 7 Astro pages (+ routing)
- Implement full design system from design/ (OKLCH tokens, Tailwind 4 @theme)
- Add 12 Astro components (Button, Badge, Card, Sidebar, Header, states)
- Add 11 React islands (AuthGuard, MessageFeed, VoiceControls, AudioVisualizer, etc.)
- Add 3 Zustand stores (UI, voice, message state)
- Add CSS architecture: dark/light themes, glassmorphism, fluid typography, animations
- Add 404, login, settings, recordings pages
- Remove 40+ legacy React SPA files
- Add Particles background and MascotChat deferred islands
- Wire WebSocket bridge for real-time messages and voice events

Build: 7 pages in ~900ms
Typecheck: clean (0 errors)
Lint: clean (0 errors)

services/frontend/src/shared/ws/socket.ts

@@ -6,9 +6,9 @@ import type {
   VoiceRecordingUploadData,
 } from "@bete/shared";
 import { useCallback, useEffect, useRef, useState } from "react";
-import type { MediaState } from "../../entities/media/types.js";
-import { createLogger } from "../lib/logger.js";
 import { getSessionToken } from "../api/client.js";
+import { createLogger } from "../lib/logger.js";
+import type { MediaState } from "../types/media.js";
 import type { ActiveSpeakerData } from "./events.js";
 
 const logger = createLogger("socket");
@@ -391,3 +391,43 @@ export function useDashboardSocket(handlers: WsHandlers) {
 
   return { status, send, socketRef: { current: _wsInstance } };
 }
+
+/**
+ * Singleton manager for the WebSocket connection.
+ * Provides imperative connect/disconnect/send access alongside useDashboardSocket.
+ */
+export class SocketManager {
+  private static _instance: SocketManager;
+
+  private constructor() {}
+
+  static getInstance(): SocketManager {
+    if (!SocketManager._instance) {
+      SocketManager._instance = new SocketManager();
+    }
+    return SocketManager._instance;
+  }
+
+  /** Ensure the WebSocket is connected (reconnects if closed). */
+  connect(): void {
+    _closed = false;
+    ensureConnected();
+  }
+
+  /** Close the WebSocket and stop reconnection. */
+  disconnect(): void {
+    _closed = true;
+    if (_reconnectTimer) clearTimeout(_reconnectTimer);
+    if (_wsInstance) {
+      _wsInstance.close();
+      _wsInstance = null;
+    }
+  }
+
+  /** Send data through the WebSocket (no-op if not connected). */
+  send(data: ArrayBuffer | string): void {
+    if (_wsInstance?.readyState === WebSocket.OPEN) {
+      _wsInstance.send(data);
+    }
+  }
+}