Update CHANGELOG.md for PackerUtils.packer abstraction removal

- Add Code Cleanup section documenting removal of PackerUtils.packer method
- Explain rationale: abstraction no longer needed since we only support Shakapacker
- Note that all tests were updated accordingly
- Provides context for this architectural simplification

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

CHANGELOG.md

@@ -28,6 +28,10 @@ Changes since the last non-beta release.
 - **Doctor rake task**: Fixed LoadError in `rake react_on_rails:doctor` when using packaged gem. The task was trying to require excluded `rakelib/task_helpers` file. [PR 1795](https://github.com/shakacode/react_on_rails/pull/1795)
 - **Shakapacker version requirements**: Fixed inconsistent version requirements between basic pack generation (6.5.1+) and advanced auto-registration features (7.0.0+). Added backward compatibility for users on Shakapacker 6.5.1-6.9.x while providing clear upgrade guidance for advanced features. Added new constants `MINIMUM_SHAKAPACKER_VERSION_FOR_AUTO_REGISTRATION` and improved version checking performance with caching. [PR 1798](https://github.com/shakacode/react_on_rails/pull/1798)
 
+#### Code Cleanup
+
+- **PackerUtils abstraction removal**: Removed unnecessary `PackerUtils.packer` abstraction method and replaced all calls with direct `::Shakapacker` usage. This simplifies the codebase by eliminating an abstraction layer that was originally created to support multiple webpack tools but is no longer needed since we only support Shakapacker. All tests updated accordingly. [PR 1798](https://github.com/shakacode/react_on_rails/pull/1798)
+
 ### [16.0.1-rc.0] - 2025-09-19
 
 #### Pro License Structure Implementation