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/shared/database/migrate.ts

@@ -0,0 +1,54 @@
+import "dotenv/config";
+import { drizzle as drizzlePostgres } from "drizzle-orm/node-postgres";
+import { migrate as migratePostgres } from "drizzle-orm/node-postgres/migrator";
+import { config } from "../../shared/config/config.js";
+import { createChildLogger } from "../../shared/logger/logger.js";
+import {
+  closeDatabase,
+  initializeDatabase,
+  withDatabaseClient,
+} from "./drizzle.js";
+import * as schema from "./schema.js";
+
+const logger = createChildLogger("migrate");
+const MIGRATION_LOCK_KEY_1 = 2026;
+const MIGRATION_LOCK_KEY_2 = 531;
+
+export async function runMigrations(): Promise<void> {
+  try {
+    logger.info("Starting PostgreSQL migrations");
+    await initializeDatabase();
+
+    try {
+      await withDatabaseClient(async (client) => {
+        const db = drizzlePostgres(client, { schema });
+
+        await client.query("SELECT pg_advisory_lock($1, $2)", [
+          MIGRATION_LOCK_KEY_1,
+          MIGRATION_LOCK_KEY_2,
+        ]);
+
+        try {
+          await migratePostgres(db, {
+            migrationsFolder: "./drizzle/migrations",
+          });
+        } finally {
+          await client.query("SELECT pg_advisory_unlock($1, $2)", [
+            MIGRATION_LOCK_KEY_1,
+            MIGRATION_LOCK_KEY_2,
+          ]);
+        }
+      });
+    } finally {
+      await closeDatabase();
+    }
+
+    logger.info("PostgreSQL migrations completed successfully");
+  } catch (error) {
+    logger.error(
+      { error: error instanceof Error ? error.message : String(error) },
+      "Migration failed",
+    );
+    throw error;
+  }
+}