chore: Add .pubignore file and update CHANGELOG for initial release of Unity and Unreal engine integrations

This commit introduces a .pubignore file to exclude Gradle build files from being published. Additionally, it updates the CHANGELOG to document the initial release of both Unity and Unreal engine integrations, highlighting key features such as multi-platform support, bidirectional communication, and comprehensive documentation.

Author: juicycleff

engines/unity/dart/.pubignore

@@ -0,0 +1,3 @@
+# Gradle build files
+android/.gradle/
+android/local.properties

engines/unity/dart/CHANGELOG.md

@@ -2,6 +2,19 @@
 
 All notable changes to the gameframework_unity package will be documented in this file.
 
+## [0.0.1] - 2026-02-06
+
+### Initial Release
+- Unity Engine integration for Flutter with multi-platform support
+- Complete desktop platform support (macOS, Windows, Linux)
+- Unity WebGL support for Flutter Web applications
+- Android and iOS Unity integration
+- AR Foundation integration tools
+- Performance monitoring capabilities
+- Full bidirectional communication between Flutter and Unity
+- Scene management and lifecycle handling
+- Comprehensive documentation and guides
+
 ## [0.4.0] - 2024-10-27
 
 ### Added