add missing gradle-wrapper.jar to fix gradlew

The jar was never committed (caught by *.jar in .gitignore).
Added a specific exception so future wrapper jars stay tracked.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.gitignore

@@ -5,6 +5,7 @@ gradle-app.setting
 # native lib outputs
 project-classes/
 *.jar
+!gradle/wrapper/gradle-wrapper.jar
 *.dex
 # Android Studio
 bin/