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/discord-gateway/src/index.ts

@@ -0,0 +1,14 @@
+import "./mock-crc.js";
+import "libsodium-wrappers";
+import "@snazzah/davey";
+import "dotenv/config";
+import { initializeDiscordGateway } from "./app/bootstrap.js";
+import { createChildLogger } from "./shared/logger/logger.js";
+
+const logger = createChildLogger("discord-gateway");
+
+// Initialize the Discord Gateway service
+initializeDiscordGateway().catch((error: unknown) => {
+  logger.error({ error }, "Failed to initialize Discord Gateway");
+  process.exit(1);
+});