feat: gateway CRUD routes — conversations, projects, missions, tasks (P1-005/006) (#72)

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

apps/gateway/src/brain/brain.module.ts

@@ -0,0 +1,19 @@
+import { Global, Module } from '@nestjs/common';
+import { createBrain, type Brain } from '@mosaic/brain';
+import type { Db } from '@mosaic/db';
+import { DB } from '../database/database.module.js';
+
+export const BRAIN = 'BRAIN';
+
+@Global()
+@Module({
+  providers: [
+    {
+      provide: BRAIN,
+      useFactory: (db: Db): Brain => createBrain(db),
+      inject: [DB],
+    },
+  ],
+  exports: [BRAIN],
+})
+export class BrainModule {}