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

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

turbo.json

@@ -0,0 +1,11 @@
+{
+  "$schema": "https://turbo.build/schema.json",
+  "globalEnv": ["NODE_ENV"],
+  "tasks": {
+    "build": { "dependsOn": ["^build"], "outputs": ["dist/**", ".next/**", "!.next/cache/**"] },
+    "typecheck": { "dependsOn": ["^build"] },
+    "test": { "dependsOn": ["^build"] },
+    "lint": {},
+    "dev": { "cache": false, "persistent": true }
+  }
+}