feat: implement all real backend endpoints, Redis pub/sub bridge, and gateway command handler

Backend (real implementations, no more stubs):
- Redis pub/sub bridge: subscribes to discord-gateway events (message/attachment/voice) and broadcasts to WS clients
- Redis command channel: backend publishes voice/media commands, discord-gateway executes and replies
- Voice service: connectVoice/disconnectVoice/getVoiceStatus via Redis commands with graceful fallback
- Media service: queue/skip/stop/volume via Redis commands, reads status from Redis cache
- Messages repository: ALL 7 methods now use real PostgreSQL queries (findMany, findById, findByChannel, create, update, delete, getAttachmentsByChannel)
- Analytics: period returns {start,end} epoch millis, overview includes hourly/topics/top_users, worst_flags as string[]
- Health check: actually queries SELECT 1 against database
- VoiceStatus type fixed: {connected, activeGuildId, activeChannelId, activeChannelName}
- Guild type: includes icon: string | null
- asyncHandler: accepts Promise<unknown> instead of Promise<void>

Discord Gateway:
- CommandHandler: subscribes to 'backend:command' Redis channel, executes voice/media commands, publishes replies
- Publishes voice:status and media:status to Redis for backend caching
- Shutdown handler updated to close command handler

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

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

@@ -2,16 +2,10 @@ 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 { queue, skip, stop, setVolume, getStatus } from "./media.service.js";
 
 const logger = createChildLogger("media.routes");
 
-const stubResponse = {
-  playing: false,
-  musicVolume: 1.0,
-  current: null,
-  queue: [],
-};
-
 export function createMediaRouter(): Router {
   const router = express.Router();
 
@@ -20,16 +14,27 @@ export function createMediaRouter(): Router {
     "/media/status",
     asyncHandler(async (_req: Request, res: Response) => {
       logger.debug("Media status requested");
-      res.json(stubResponse);
+      const status = await getStatus();
+      res.json(status);
     }),
   );
 
   // POST /api/media/queue
   router.post(
     "/media/queue",
-    asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media queue requested (stub)");
-      res.json(stubResponse);
+    asyncHandler(async (req: Request, res: Response) => {
+      const source = req.body?.source as string | undefined;
+      if (!source) {
+        res.status(400).json({
+          error: "VALIDATION_ERROR",
+          message: "source is required",
+        });
+        return;
+      }
+      const mode = (req.body?.mode as "music" | "screen") ?? "music";
+      logger.debug({ source, mode }, "Media queue requested");
+      const state = await queue(source, mode);
+      res.json(state);
     }),
   );
 
@@ -37,8 +42,9 @@ export function createMediaRouter(): Router {
   router.post(
     "/media/skip",
     asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media skip requested (stub)");
-      res.json(stubResponse);
+      logger.debug("Media skip requested");
+      const state = await skip();
+      res.json(state);
     }),
   );
 
@@ -46,17 +52,27 @@ export function createMediaRouter(): Router {
   router.post(
     "/media/stop",
     asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media stop requested (stub)");
-      res.json(stubResponse);
+      logger.debug("Media stop requested");
+      const state = await stop();
+      res.json(state);
     }),
   );
 
   // POST /api/media/volume
   router.post(
     "/media/volume",
-    asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media volume requested (stub)");
-      res.json(stubResponse);
+    asyncHandler(async (req: Request, res: Response) => {
+      const volume = Number(req.body?.volume ?? 1.0);
+      if (Number.isNaN(volume) || volume < 0 || volume > 1) {
+        res.status(400).json({
+          error: "VALIDATION_ERROR",
+          message: "volume must be a number between 0 and 1",
+        });
+        return;
+      }
+      logger.debug({ volume }, "Media volume requested");
+      const state = await setVolume(volume);
+      res.json(state);
     }),
   );