feat: scaffold monorepo with Turborepo + NestJS + Next.js

- Turborepo monorepo with pnpm workspaces
- apps/api: NestJS 11.x with CQRS module
- apps/web: Next.js 14 App Router + TailwindCSS
- src/modules/shared: base entities, Result pattern, value objects
- TypeScript 5.7+ strict mode, shared tsconfig base
- Build pipeline: dev, build, lint, test, typecheck

Co-Authored-By: Paperclip <noreply@paperclip.ing>

turbo.json

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://turbo.build/schema.json",
+  "tasks": {
+    "build": {
+      "dependsOn": ["^build"],
+      "outputs": ["dist/**", ".next/**"]
+    },
+    "dev": {
+      "cache": false,
+      "persistent": true
+    },
+    "lint": {
+      "dependsOn": ["^build"]
+    },
+    "test": {
+      "dependsOn": ["^build"]
+    },
+    "typecheck": {
+      "dependsOn": ["^build"]
+    }
+  }
+}