feat(backend): implement all missing endpoints, real analytics queries, and WebSocket server

- Replace stub analytics.repository.ts with real PostgreSQL queries using pg.Pool
- Add /api/guilds, /api/config, /api/auth/login, /api/ui-state (GET/POST)
- Add /api/review, /api/recordings, /api/analysis/search
- Add /api/messages/:id/reanalyze endpoint
- Add /api/analytics/heatmap and /api/analytics/topics
- Implement media routes (stub responses, backend has no Discord voice client)
- Add WebSocket server at /ws with heartbeat and broadcast functions
- Fix analytics route paths to match frontend contract (dual paths for backward compat)
- Export getPool() from database module for raw SQL queries
- Register all new routers in app.ts

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/backend/src/modules/recordings/recordings.routes.ts

@@ -0,0 +1,24 @@
+import type { Request, Response, Router } from "express";
+import express from "express";
+import { createChildLogger } from "../../shared/logger/index.js";
+import { asyncHandler } from "../../shared/middlewares/index.js";
+import { recordingsService } from "./recordings.service.js";
+
+const logger = createChildLogger("recordings.routes");
+
+export function createRecordingsRouter(): Router {
+  const router = express.Router();
+
+  // GET /api/recordings
+  router.get(
+    "/recordings",
+    asyncHandler(async (req: Request, res: Response) => {
+      const limit = Number(req.query.limit) || 50;
+      logger.debug({ limit }, "Fetching recordings");
+      const result = await recordingsService.getRecent(limit);
+      res.json(result);
+    }),
+  );
+
+  return router;
+}

services/backend/src/modules/recordings/recordings.service.ts

@@ -0,0 +1,26 @@
+import { sql } from "drizzle-orm";
+import { getDatabase } from "../../shared/database/index.js";
+import { createChildLogger } from "../../shared/logger/index.js";
+
+const logger = createChildLogger("recordings.service");
+
+export class RecordingsService {
+  async getRecent(limit = 50) {
+    const db = getDatabase();
+    logger.debug({ limit }, "Fetching recent voice recordings");
+
+    const { rows } = await db.execute(sql`
+      SELECT
+        id, user_id, username, avatar_url, guild_id, channel_id,
+        channel_name, filename, size_bytes, download_url,
+        upload_status, upload_error, created_at, uploaded_at
+      FROM voice_recordings
+      ORDER BY created_at DESC
+      LIMIT ${limit}
+    `);
+
+    return rows;
+  }
+}
+
+export const recordingsService = new RecordingsService();