feat: auth middleware, brain data layer, Valkey queue (P1-002/003/004) (#71)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/database/database.module.ts

@@ -0,0 +1,28 @@
+import { Global, Inject, Module, type OnApplicationShutdown } from '@nestjs/common';
+import { createDb, type Db, type DbHandle } from '@mosaic/db';
+
+export const DB_HANDLE = 'DB_HANDLE';
+export const DB = 'DB';
+
+@Global()
+@Module({
+  providers: [
+    {
+      provide: DB_HANDLE,
+      useFactory: (): DbHandle => createDb(),
+    },
+    {
+      provide: DB,
+      useFactory: (handle: DbHandle): Db => handle.db,
+      inject: [DB_HANDLE],
+    },
+  ],
+  exports: [DB],
+})
+export class DatabaseModule implements OnApplicationShutdown {
+  constructor(@Inject(DB_HANDLE) private readonly handle: DbHandle) {}
+
+  async onApplicationShutdown(): Promise<void> {
+    await this.handle.close();
+  }
+}