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/http/server.ts

@@ -0,0 +1,25 @@
+import { config } from "../shared/config/index.js";
+import { initializeDatabase } from "../shared/database/index.js";
+import { createChildLogger } from "../shared/logger/index.js";
+import { createHttpApp } from "./app.js";
+
+const logger = createChildLogger("http.server");
+
+export async function startHttpServer() {
+  await initializeDatabase();
+
+  const app = createHttpApp();
+  const port = config.WEBSERVER_PORT;
+
+  return new Promise<void>((resolve, reject) => {
+    const server = app.listen(port, () => {
+      logger.info({ port }, "HTTP server started");
+      resolve();
+    });
+
+    server.on("error", (err) => {
+      logger.error({ err }, "HTTP server error");
+      reject(err);
+    });
+  });
+}