fix: write local.properties with sdk.dir for Gradle

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-release.yml

@@ -17,8 +17,8 @@ jobs:
         run: |
           echo "Java: $(java --version 2>&1 | head -1)"
           echo "ANDROID_HOME: $ANDROID_HOME"
-          test -n "$ANDROID_HOME" || { echo "ERROR: ANDROID_HOME not set"; exit 1; }
-          ls "$ANDROID_HOME/platforms" > /dev/null 2>&1 || echo "WARNING: Cannot list ANDROID_HOME (permissions?), build may still work via gradle"
+          echo "sdk.dir=$ANDROID_HOME" > local.properties
+          cat local.properties
 
       - name: Build Release APK
         shell: bash