chore: bump version to 4.0.0

BREAKING CHANGE: Major release with Decorator API and JIT compilation.

This release introduces a modern Decorator API as the recommended approach,
while maintaining full backward compatibility with the BaseMapper API.

The version was incorrectly released as 3.2.0 by semantic-release.
This commit corrects it to 4.0.0 to properly reflect the major changes:

- New Decorator API with TC39 Stage 3 decorators
- JIT compilation for 17.28x better performance
- class-transformer compatibility layer
- Zero dependencies (no reflect-metadata)

No breaking changes for existing BaseMapper users.

Author: Isqanderm

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [4.0.0] - 2025-10-14
+
+### BREAKING CHANGES
+
+This is a **major release** introducing a modern Decorator API with JIT compilation. While the BaseMapper API remains fully supported for backward compatibility, the new Decorator API is now the recommended approach.
+
+**Migration:** No breaking changes for existing BaseMapper users. The new Decorator API is opt-in. See [Migration Guide](docs/MIGRATION_GUIDE.md) for details.
+
 ### Added
 
 - **Performance Benchmarks vs class-transformer** - Comprehensive comparison showing om-data-mapper is **17.28x faster** on average

package.json

@@ -1,6 +1,6 @@
 {
   "name": "om-data-mapper",
-  "version": "3.2.0",
+  "version": "4.0.0",
   "description": "High-performance TypeScript/JavaScript data mapper with JIT compilation for ultra-fast object transformations",
   "private": false,
   "main": "build/index.js",