Revert toolchain bump; target 35 on top of AGP 8.1.2

The compileSdk 35 path forced AGP 8.5.0, which in turn broke
mergeJniLibFolders against rust-android-gradle 0.9.6 with "Duplicate
resources" for every ABI's libproxydroid_tun2socks.so. Neither
packagingOptions.jniLibs.pickFirsts (wrong phase) nor srcDirs
dedupe (duplicates come from AGP's auto-registration of cargoBuild
task outputs, not from srcDirs) resolves it, and no released
rust-android-gradle plugin is compatible with AGP 8.5+.

Sidestep the whole upgrade: AGP only requires compileSdk to be
high enough to reference APIs the code actually uses; targetSdk is
a manifest declaration Play reads, and targetSdk > compileSdk is
allowed. Set targetSdk to 35 (Play's current floor) on top of the
existing toolchain:

  - AGP                     stays 8.1.2
  - Gradle                  stays 8.4
  - Kotlin                  stays 1.9.10
  - Compose Compiler ext    stays 1.5.3
  - compileSdk              stays 34
  - minSdk                  21 -> 24
  - targetSdk               33 -> 35

Mirror changes (dl.google.cn, Aliyun, Tencent Cloud) are kept.
Drop the AGP-8.5-specific JNI dedupe workaround.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: madeye

app/build.gradle

@@ -12,7 +12,7 @@ if (localPropsFile.exists()) {
 
 android {
     namespace 'org.proxydroid'
-    compileSdk 35
+    compileSdk 34
     ndkVersion "25.1.8937393"
 
     signingConfigs {
@@ -76,7 +76,7 @@ android {
     }
 
     composeOptions {
-        kotlinCompilerExtensionVersion '1.5.15'
+        kotlinCompilerExtensionVersion '1.5.3'
     }
 
     packagingOptions {
@@ -86,17 +86,6 @@ android {
     }
 }
 
-// rust-android-gradle 0.9.6 ends up registering its build/rustJniLibs/<abi>
-// directory in jniLibs.srcDirs twice under AGP 8.5+, causing
-// mergeJniLibFolders to fail with "Duplicate resources" on every ABI's .so.
-// Deduplicate srcDirs at configure time. MergeSourceSetFolders is not a
-// Copy task, so duplicatesStrategy doesn't help here.
-afterEvaluate {
-    android.sourceSets.configureEach { sourceSet ->
-        sourceSet.jniLibs.srcDirs = sourceSet.jniLibs.srcDirs.toSet().toList()
-    }
-}
-
 cargo {
     module = "src/main/rust/proxydroid-tun2socks"
     libname = "proxydroid_tun2socks"

build.gradle

@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.9.25'
+    ext.kotlin_version = '1.9.10'
     repositories {
         // Use Google's China mirror so the build works from networks where
         // dl.google.com is unreachable. The mirror serves the same artifacts.
@@ -13,7 +13,7 @@ buildscript {
         gradlePluginPortal()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:8.5.0'
+        classpath 'com.android.tools.build:gradle:8.1.2'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
         classpath 'org.mozilla.rust-android-gradle:plugin:0.9.6'
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://mirrors.cloud.tencent.com/gradle/gradle-8.7-bin.zip
+distributionUrl=https\://mirrors.cloud.tencent.com/gradle/gradle-8.4-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists