chore: update Android test app dependencies to latest stable versions

- Update AndroidX AppCompat from 1.6.1 to 1.7.1 (latest stable)
- Update AndroidX Activity from 1.7.0 to 1.8.2
- Update AndroidX Core from 1.10.0 to 1.12.0
- Update AndroidX Fragment from 1.5.6 to 1.6.2
- Update Core Splash Screen from 1.0.0 to 1.0.1
- Update AndroidX WebKit from 1.6.1 to 1.8.0
- Update compile/target SDK from 33 to 34
- Update Gradle troubleshooting guide with latest versions

Dependency updates:
- androidx.appcompat:appcompat: 1.6.1 → 1.7.1
- androidx.activity:activity: 1.7.0 → 1.8.2
- androidx.core:core: 1.10.0 → 1.12.0
- androidx.fragment:fragment: 1.5.6 → 1.6.2
- androidx.core:core-splashscreen: 1.0.0 → 1.0.1
- androidx.webkit:webkit: 1.6.1 → 1.8.0
- compileSdkVersion: 33 → 34
- targetSdkVersion: 33 → 34

Documentation updates:
- Updated Gradle troubleshooting guide with latest versions
- Added dependency update section
- Updated version compatibility table
- Added AndroidX dependency update examples

Files: 2 modified
- Modified: android/variables.gradle (updated all AndroidX versions)
- Modified: GRADLE_TROUBLESHOOTING.md (updated documentation)

test-apps/android-test/GRADLE_TROUBLESHOOTING.md

@@ -0,0 +1,160 @@
+# Android Test App Gradle Sync Troubleshooting
+
+## Problem: Gradle Sync Failure
+
+**Error Message:**
+```
+Unable to find method 'org.gradle.api.artifacts.Dependency org.gradle.api.artifacts.dsl.DependencyHandler.module(java.lang.Object)'
+```
+
+## Root Cause
+
+The Android test app was using **Gradle 9.0-milestone-1** (pre-release) with **Android Gradle Plugin 8.0.0**, causing version incompatibility issues.
+
+## Solution Applied
+
+### 1. Updated Gradle Version
+**File:** `android/gradle/wrapper/gradle-wrapper.properties`
+```properties
+# Changed from:
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.0-milestone-1-bin.zip
+
+# To:
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.13-bin.zip
+```
+
+### 2. Updated Android Gradle Plugin
+**File:** `android/build.gradle`
+```gradle
+// Changed from:
+classpath 'com.android.tools.build:gradle:8.0.0'
+
+// To:
+classpath 'com.android.tools.build:gradle:8.13.0'
+```
+
+### 3. Updated Google Services Plugin
+```gradle
+// Changed from:
+classpath 'com.google.gms:google-services:4.3.15'
+
+// To:
+classpath 'com.google.gms:google-services:4.4.0'
+```
+
+### 4. Updated AndroidX Dependencies
+**File:** `android/variables.gradle`
+```gradle
+// Updated to latest stable versions:
+androidxAppCompatVersion = '1.7.1'        // was 1.6.1
+androidxActivityVersion = '1.8.2'          // was 1.7.0
+androidxCoreVersion = '1.12.0'             // was 1.10.0
+androidxFragmentVersion = '1.6.2'         // was 1.5.6
+coreSplashScreenVersion = '1.0.1'          // was 1.0.0
+androidxWebkitVersion = '1.8.0'            // was 1.6.1
+compileSdkVersion = 34                     // was 33
+targetSdkVersion = 34                      // was 33
+```
+
+## Manual Fix Steps
+
+If you encounter this issue again:
+
+### Step 1: Clean Gradle Cache
+```bash
+cd test-apps/android-test/android
+./gradlew clean
+./gradlew --stop
+```
+
+### Step 2: Clear Gradle Wrapper Cache
+```bash
+rm -rf ~/.gradle/wrapper/dists/gradle-9.0-milestone-1*
+```
+
+### Step 3: Re-sync Project
+In Android Studio:
+1. Click **File** → **Sync Project with Gradle Files**
+2. Or click the **Sync Now** link in the error banner
+
+### Step 4: If Still Failing
+```bash
+# Delete all Gradle caches
+rm -rf ~/.gradle/caches
+rm -rf ~/.gradle/wrapper
+
+# Re-download Gradle
+cd test-apps/android-test/android
+./gradlew wrapper --gradle-version 8.4
+```
+
+## Prevention
+
+### Use Stable Versions
+Always use stable, tested version combinations:
+
+| Android Gradle Plugin | Gradle Version | Status |
+|----------------------|----------------|---------|
+| 8.13.0 | 8.13 | ✅ Latest Stable |
+| 8.1.4 | 8.4 | ✅ Stable |
+| 8.0.0 | 8.0 | ✅ Stable |
+| 7.4.2 | 7.5 | ✅ Stable |
+| 8.0.0 | 9.0-milestone-1 | ❌ Incompatible |
+
+### Version Compatibility Check
+- **Android Gradle Plugin 8.13.0** requires **Gradle 8.0+**
+- **Gradle 8.13** is the latest stable version
+- **AndroidX AppCompat 1.7.1** is the latest stable version
+- Avoid pre-release versions in production
+
+## Additional Troubleshooting
+
+### If Sync Still Fails
+
+1. **Check Java Version**
+   ```bash
+   java -version
+   # Should be Java 17+ for AGP 8.1.4
+   ```
+
+2. **Check Android SDK**
+   ```bash
+   echo $ANDROID_HOME
+   # Should point to Android SDK location
+   ```
+
+3. **Check Local Properties**
+   ```bash
+   # Verify android/local.properties exists
+   cat test-apps/android-test/android/local.properties
+   ```
+
+4. **Recreate Project**
+   ```bash
+   cd test-apps/android-test
+   rm -rf android/
+   npx cap add android
+   ```
+
+## Success Indicators
+
+After applying the fix, you should see:
+- ✅ **Gradle sync successful**
+- ✅ **No red error banners**
+- ✅ **Build.gradle file opens without errors**
+- ✅ **Project structure loads correctly**
+
+## Next Steps
+
+Once Gradle sync is successful:
+1. **Build the project**: `./gradlew build`
+2. **Run on device**: `npx cap run android`
+3. **Test plugin functionality**: Use the test API server
+4. **Validate notifications**: Test the Daily Notification Plugin
+
+## Related Issues
+
+- **Build failures**: Usually resolved by Gradle sync fix
+- **Plugin not found**: Check Capacitor plugin installation
+- **Permission errors**: Verify Android manifest permissions
+- **Runtime crashes**: Check plugin initialization code