fix(ci): 为 gradlew 与构建脚本补上可执行位

Windows 提交时丢失了可执行位，导致 GitHub Actions 上 ./gradlew 报 Permission denied。

Author: qpalzm2332933171-droid

.github/workflows/build.yml

@@ -27,6 +27,7 @@ jobs:
       - name: Show toolchain versions
         run: |
           java -version
+          ls -l gradlew
           ./gradlew --version
 
       - name: Build debug APK