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>

apps/web/postcss.config.js

@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+};