chore(frontend): refactor navigation and DI setup, remove unused shared module

- Replaced `initKoin` with `startKoin` for DI initialization consistency across platforms.
- Introduced `StateNavigationPort` with `StateFlow` to streamline navigation state management.
- Migrated `AppScreen` to sealed class with route mapping for better navigation handling.
- Deleted unused `frontend/shared` module and removed related dependencies from build files.
- Cleaned up legacy navigation and Redux-related code, aligning with MVVM architecture.

frontend/shells/meldestelle-portal/build.gradle.kts

@@ -63,7 +63,7 @@ kotlin {
   sourceSets {
     commonMain.dependencies {
       // Shared modules
-      implementation(projects.frontend.shared)
+      // implementation(projects.frontend.shared) // REMOVED: Shared module deleted
       implementation(projects.frontend.core.domain)
       implementation(projects.frontend.core.designSystem)
       implementation(projects.frontend.core.navigation)

frontend/shells/meldestelle-portal/src/commonMain/kotlin/MainApp.kt

@@ -6,7 +6,7 @@ import androidx.compose.foundation.verticalScroll
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import androidx.compose.runtime.collectAsState
-import at.mocode.clients.shared.navigation.AppScreen
+import at.mocode.frontend.core.navigation.AppScreen
 import at.mocode.frontend.core.auth.data.AuthTokenManager
 import at.mocode.frontend.core.auth.presentation.LoginScreen
 import at.mocode.frontend.core.auth.presentation.LoginViewModel
@@ -14,6 +14,7 @@ import at.mocode.ping.feature.presentation.PingScreen
 import at.mocode.ping.feature.presentation.PingViewModel
 import at.mocode.frontend.core.designsystem.components.AppFooter
 import at.mocode.frontend.core.designsystem.theme.AppTheme
+import navigation.StateNavigationPort
 import org.koin.compose.koinInject
 import org.koin.compose.viewmodel.koinViewModel
 
@@ -25,7 +26,9 @@ fun MainApp() {
       modifier = Modifier.fillMaxSize(),
       color = MaterialTheme.colorScheme.background
     ) {
-      var currentScreen by remember { mutableStateOf<AppScreen>(AppScreen.Landing) }
+      // Resolve NavigationPort to observe state changes
+      val navigationPort = koinInject<StateNavigationPort>()
+      val currentScreen by navigationPort.currentScreen.collectAsState()
 
       // Resolve AuthTokenManager from Koin
       val authTokenManager = koinInject<AuthTokenManager>()
@@ -36,31 +39,31 @@ fun MainApp() {
 
       when (currentScreen) {
         is AppScreen.Landing -> LandingScreen(
-          onPrimaryCta = { currentScreen = AppScreen.Login },
-          onSecondary = { currentScreen = AppScreen.Home }
+          onPrimaryCta = { navigationPort.navigateToScreen(AppScreen.Login) },
+          onSecondary = { navigationPort.navigateToScreen(AppScreen.Home) }
         )
 
         is AppScreen.Home -> WelcomeScreen(
           authTokenManager = authTokenManager,
-          onOpenPing = { currentScreen = AppScreen.Ping },
-          onOpenLogin = { currentScreen = AppScreen.Login },
-          onOpenProfile = { currentScreen = AppScreen.Profile }
+          onOpenPing = { navigationPort.navigateToScreen(AppScreen.Ping) },
+          onOpenLogin = { navigationPort.navigateToScreen(AppScreen.Login) },
+          onOpenProfile = { navigationPort.navigateToScreen(AppScreen.Profile) }
         )
 
         is AppScreen.Login -> LoginScreen(
           viewModel = loginViewModel,
-          onLoginSuccess = { currentScreen = AppScreen.Profile },
-          onBack = { currentScreen = AppScreen.Home }
+          onLoginSuccess = { navigationPort.navigateToScreen(AppScreen.Profile) },
+          onBack = { navigationPort.navigateToScreen(AppScreen.Home) }
         )
 
         is AppScreen.Ping -> PingScreen(
           viewModel = pingViewModel,
-          onBack = { currentScreen = AppScreen.Home } // Navigate back to Home
+          onBack = { navigationPort.navigateToScreen(AppScreen.Home) } // Navigate back to Home
         )
 
         is AppScreen.Profile -> AuthStatusScreen(
           authTokenManager = authTokenManager,
-          onBackToHome = { currentScreen = AppScreen.Home }
+          onBackToHome = { navigationPort.navigateToScreen(AppScreen.Home) }
         )
 
         else -> {}

frontend/shells/meldestelle-portal/src/commonMain/kotlin/navigation/ShellNavigationModule.kt

@@ -2,9 +2,13 @@ package navigation
 
 import at.mocode.frontend.core.auth.data.AuthTokenManager
 import at.mocode.frontend.core.domain.models.User
+import at.mocode.frontend.core.navigation.AppScreen
 import at.mocode.frontend.core.navigation.CurrentUserProvider
 import at.mocode.frontend.core.navigation.DeepLinkHandler
 import at.mocode.frontend.core.navigation.NavigationPort
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.asStateFlow
 import org.koin.dsl.module
 
 class ShellCurrentUserProvider(
@@ -23,17 +27,29 @@ class ShellCurrentUserProvider(
   }
 }
 
-class NoopNavigationPort : NavigationPort {
-  var lastRoute: String? = null
+/**
+ * A real implementation of NavigationPort that updates a StateFlow.
+ * This allows the MainApp to observe changes and update the UI.
+ */
+class StateNavigationPort : NavigationPort {
+  private val _currentScreen = MutableStateFlow<AppScreen>(AppScreen.Landing)
+  val currentScreen: StateFlow<AppScreen> = _currentScreen.asStateFlow()
+
   override fun navigateTo(route: String) {
-    lastRoute = route
-    // Simple logging; actual routing is handled elsewhere in the shell
-    println("[NavigationPort] navigateTo $route")
+    val screen = AppScreen.fromRoute(route)
+    println("[NavigationPort] navigateTo $route -> $screen")
+    _currentScreen.value = screen
+  }
+
+  fun navigateToScreen(screen: AppScreen) {
+      _currentScreen.value = screen
   }
 }
 
 val navigationModule = module {
   single<CurrentUserProvider> { ShellCurrentUserProvider(get()) }
-  single<NavigationPort> { NoopNavigationPort() }
+  // Bind as both NavigationPort (for Core) and StateNavigationPort (for Shell)
+  single { StateNavigationPort() }
+  single<NavigationPort> { get<StateNavigationPort>() }
   single { DeepLinkHandler(get(), get()) }
 }

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

@@ -7,12 +7,12 @@ import at.mocode.frontend.core.localdb.localDbModule
 import at.mocode.frontend.core.network.networkModule
 import at.mocode.frontend.core.sync.di.syncModule
 import at.mocode.ping.feature.di.pingFeatureModule
-import at.mocode.shared.di.initKoin
 import kotlinx.browser.document
 import kotlinx.coroutines.MainScope
 import kotlinx.coroutines.launch
 import navigation.navigationModule
 import org.koin.core.context.GlobalContext
+import org.koin.core.context.startKoin
 import org.koin.core.context.loadKoinModules
 import org.koin.dsl.module
 import org.w3c.dom.HTMLElement
@@ -23,7 +23,7 @@ fun main() {
 
   // 1. Initialize DI (Koin) with static modules
   try {
-    initKoin { modules(networkModule, localDbModule, syncModule, pingFeatureModule, authModule, navigationModule) }
+    startKoin { modules(networkModule, localDbModule, syncModule, pingFeatureModule, authModule, navigationModule) }
     console.log("[WebApp] Koin initialized with static modules")
   } catch (e: dynamic) {
     console.warn("[WebApp] Koin initialization warning:", e)

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

@@ -2,7 +2,6 @@ import androidx.compose.ui.window.Window
 import androidx.compose.ui.window.application
 import androidx.compose.ui.window.WindowState
 import androidx.compose.ui.unit.dp
-import at.mocode.shared.di.initKoin
 import at.mocode.frontend.core.network.networkModule
 import at.mocode.frontend.core.auth.di.authModule
 import at.mocode.frontend.core.sync.di.syncModule
@@ -12,6 +11,7 @@ import at.mocode.frontend.core.localdb.DatabaseProvider
 import at.mocode.frontend.core.localdb.localDbModule
 import navigation.navigationModule
 import kotlinx.coroutines.runBlocking
+import org.koin.core.context.startKoin
 import org.koin.core.context.loadKoinModules
 import org.koin.dsl.module
 
@@ -19,7 +19,7 @@ fun main() = application {
   // Initialize DI (Koin) with shared modules + network module
   try {
     // Updated: Only load the consolidated pingFeatureModule from at.mocode.ping.feature.di
-    initKoin { modules(networkModule, syncModule, pingFeatureModule, authModule, navigationModule, localDbModule) }
+    startKoin { modules(networkModule, syncModule, pingFeatureModule, authModule, navigationModule, localDbModule) }
     println("[DesktopApp] Koin initialized with networkModule + authModule + navigationModule + pingFeatureModule + localDbModule")
   } catch (e: Exception) {
     println("[DesktopApp] Koin initialization warning: ${e.message}")