Monorepo skeleton, Prisma schema, core domain and services with tests

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

packages/db/prisma.config.ts

@@ -0,0 +1,11 @@
+import path from 'node:path';
+import { config } from 'dotenv';
+import { defineConfig, env } from 'prisma/config';
+
+config({ path: path.resolve(import.meta.dirname, '../../.env'), quiet: true });
+
+export default defineConfig({
+  schema: 'prisma/schema.prisma',
+  migrations: { path: 'prisma/migrations', seed: 'tsx src/seed/index.ts' },
+  datasource: { url: env('DATABASE_URL') },
+});