✨ feat: implement core Cereale library for JSON mapping and validation

- 🎨 add Spring-like decorators (@JsonSerialize, @JsonDeserialize, etc.)
- ⚙️ implement JsonMapper and metadata storage for transformations
- 🧪 add comprehensive test suite using Vitest
- 📝 add README, CONTRIBUTING, and API documentation
- 👷 setup GitHub Actions CI workflow
- 🔧 configure TypeScript and project settings

tsconfig.cjs.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "CommonJS",
+    "moduleResolution": "Bundler",
+    "outDir": "dist/cjs",
+    "declaration": true
+  }
+}