集成 Timber 日志框架，降级 AGP/Gradle 适配 JDK 17，修复构建设置

- 新增 PosefitApplication 初始化 Timber DebugTree

- WebRtcSenderClient/MainActivity/SimpleSdpObserver 添加 Timber 日志

- AGP 9.2.1 → 8.7.3，Gradle 9.4.1 → 8.11.1 适配 JDK 17

- compileSdk/targetSdk 恢复为 34，minSdk 保持 29 支持 Android 10

- 添加 android.useAndroidX=true 修复构建检查

- 删除 gradle-daemon-jvm.properties (JDK 21 残留配置)

- 信令端口默认改为 8765

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-agp = "9.2.1"
+agp = "8.7.3"
 kotlin = "2.0.0"
 composeBom = "2024.02.00"
 composeCompiler = "1.5.8"
@@ -11,8 +11,10 @@ junitVersion = "1.1.5"
 espressoCore = "3.5.1"
 appcompat = "1.6.1"
 material = "1.10.0"
+timber = "5.0.1"
 
 [libraries]
+timber = { group = "com.jakewharton.timber", name = "timber", version.ref = "timber" }
 junit = { group = "junit", name = "junit", version.ref = "junit" }
 ext-junit = { group = "androidx.test.ext", name = "junit", version.ref = "junitVersion" }
 espresso-core = { group = "androidx.test.espresso", name = "espresso-core", version.ref = "espressoCore" }