refactor: split monolith into 3 microservices (frontend, backend, discord-gateway)

- Extract services into services/{frontend,backend,discord-gateway}
- Create packages/shared/ for shared logger, errors, utils, types
- Setup Modular MVC pattern in backend (controller→service→repository)
- Setup event-driven architecture in discord-gateway with Redis pub/sub
- Move Docker files to infra/docker/ with per-service Dockerfiles
- Update docker-compose.yml to use Traefik-only routing (no port exposes)
- Update GitHub Actions deploy workflow for multi-service matrix build
- Fix all import paths and resolve type errors across all services
- All 3 services pass tsc --noEmit clean

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

services/backend/src/modules/messages/routes/index.ts

@@ -0,0 +1,26 @@
+import type { Router } from "express";
+import express from "express";
+import {
+  handleGetAttachmentsByChannel,
+  handleGetMessageById,
+  handleGetMessagesByChannel,
+  handleListMessages,
+} from "../messages.controller.js";
+
+export function createMessagesRouter(): Router {
+  const router = express.Router();
+
+  // GET /api/messages - List messages
+  router.get("/messages", handleListMessages);
+
+  // GET /api/messages/:channelId - Get messages by channel
+  router.get("/messages/:channelId", handleGetMessagesByChannel);
+
+  // GET /api/messages/:channelId/attachments - Get attachments by channel
+  router.get("/messages/:channelId/attachments", handleGetAttachmentsByChannel);
+
+  // GET /api/messages/:id - Get single message by ID
+  router.get("/messages/:id", handleGetMessageById);
+
+  return router;
+}