chore: 清理gradle废弃配置，移除enableJetifier

- 移除已废弃的enableJetifier=true
- 添加generateSyncIssueWhenLibraryConstraintsAreEnabled抑制重复警告
- 其余deprecated属性暂保留（删除会导致构建失败）

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

android-app/build.gradle

@@ -6,7 +6,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:9.0.0'
+        classpath 'com.android.tools.build:gradle:9.0.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
     }
 }