refactor(ping-feature): integrate DI refactor, enhance web build, and update feature workflow

Refactored the `ping-feature` module to adopt centralized `HttpClient` through Koin DI, replacing legacy implementations. Added secure API calls with improved error handling and updated Webpack build scripts to resolve worker path issues. Enhanced `PingScreen` with extended functionality, UI updates, and aligned test cases for the new architecture. Consolidated feature workflows and finalized documentation with a comprehensive feature implementation guide.

frontend/shells/meldestelle-portal/src/jvmMain/kotlin/main.kt

@@ -6,7 +6,8 @@ import at.mocode.shared.di.initKoin
 import at.mocode.frontend.core.network.networkModule
 import at.mocode.clients.authfeature.di.authFeatureModule
 import at.mocode.frontend.core.sync.di.syncModule
-import at.mocode.ping.feature.di.pingFeatureModule
+import at.mocode.clients.pingfeature.di.pingFeatureModule
+import at.mocode.ping.feature.di.pingSyncFeatureModule
 import at.mocode.frontend.core.localdb.AppDatabase
 import at.mocode.frontend.core.localdb.DatabaseProvider
 import navigation.navigationModule
@@ -17,7 +18,7 @@ import org.koin.dsl.module
 fun main() = application {
   // Initialize DI (Koin) with shared modules + network module
   try {
-    initKoin { modules(networkModule, syncModule, pingFeatureModule, authFeatureModule, navigationModule) }
+    initKoin { modules(networkModule, syncModule, pingFeatureModule, pingSyncFeatureModule, authFeatureModule, navigationModule) }
     println("[DesktopApp] Koin initialized with networkModule + authFeatureModule + navigationModule")
   } catch (e: Exception) {
     println("[DesktopApp] Koin initialization warning: ${e.message}")