fix: release build crash on Android 15+ (API 36)

- Add ProGuard rules for Flutter plugins (path_provider, local_notifications, receive_sharing_intent, etc.)
- Upgrade Go to 1.25.6 for 16KB page alignment support
- Expand ProGuard rules for Go backend and Kotlin coroutines
- Fix R8 stripping plugin implementations in release builds

.github/workflows/release.yml

@@ -71,7 +71,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
+          go-version: "1.25"
           cache-dependency-path: go_backend/go.sum
 
       # Cache Gradle for faster builds
@@ -174,7 +174,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v5
         with:
-          go-version: "1.21"
+          go-version: "1.25"
           cache-dependency-path: go_backend/go.sum
 
       # Cache CocoaPods