Integrate Ktor HTTP clients and repositories for Veranstalter and Turnier features:

- Add `ApiRoutes` for central backend routing configuration.
- Implement `DefaultVeranstalterRepository` and `DefaultTurnierRepository` with Ktor clients.
- Add domain models (`Turnier`, `Bewerb`, `Abteilung`, `Veranstalter`) and respective repository interfaces.
- Replace fake VeranstalterRepository with real implementation.
- Update DI with `veranstalterModule` and HTTP client injection.
- Simplify TokenProvider and update HttpClient setup (timeouts, retries, logging).
- Mark roadmap tasks B-2 as partially complete.

frontend/core/network/src/commonMain/kotlin/at/mocode/frontend/core/network/ApiRoutes.kt

@@ -0,0 +1,21 @@
+package at.mocode.frontend.core.network
+
+/**
+ * Zentrale API-Routen-Konfiguration. Versionierung erfolgt über den Prefix /api/v3.
+ */
+object ApiRoutes {
+  const val API_PREFIX = "/api/v3"
+
+  object Veranstalter {
+    const val ROOT = "$API_PREFIX/veranstalter"
+  }
+
+  object Turniere {
+    const val ROOT = "$API_PREFIX/turniere"
+    fun bewerbe(turnierId: Long): String = "$ROOT/$turnierId/bewerbe"
+  }
+
+  object Bewerbe {
+    fun abteilungen(bewerbId: Long): String = "$API_PREFIX/bewerbe/$bewerbId/abteilungen"
+  }
+}

frontend/core/network/src/commonMain/kotlin/at/mocode/frontend/core/network/HttpClientFactory.kt

@@ -0,0 +1 @@
+// Removed: superseded by NetworkModule.kt

frontend/core/network/src/commonMain/kotlin/at/mocode/frontend/core/network/NetworkModule.kt

@@ -13,9 +13,7 @@ import org.koin.dsl.module
 /**
  * Schnittstelle zur Token-Bereitstellung – entkoppelt core-network von core-auth.
  */
-interface TokenProvider {
-  fun getAccessToken(): String?
-}
+interface TokenProvider { fun getAccessToken(): String? }
 
 /**
  * Koin-Modul mit zwei HttpClient-Instanzen:
@@ -28,16 +26,15 @@ val networkModule = module {
   single(named("baseHttpClient")) {
     HttpClient {
       install(ContentNegotiation) {
-        json(Json { ignoreUnknownKeys = true; isLenient = true; encodeDefaults = true })
-      }
-      install(Logging) {
-        logger = object : Logger {
-          override fun log(message: String) {
-            println("[baseClient] $message")
+        json(
+          Json {
+            ignoreUnknownKeys = true
+            explicitNulls = false
+            coerceInputValues = true
           }
-        }
-        level = LogLevel.INFO
+        )
       }
+      install(Logging) { logger = Logger.SIMPLE; level = LogLevel.NONE }
     }
   }
 
@@ -47,29 +44,29 @@ val networkModule = module {
 
     HttpClient {
       install(ContentNegotiation) {
-        json(Json { ignoreUnknownKeys = true; isLenient = true; encodeDefaults = true })
+        json(
+          Json {
+            ignoreUnknownKeys = true
+            explicitNulls = false
+            coerceInputValues = true
+          }
+        )
       }
       install(HttpTimeout) {
+        // Defaults laut Spezifikation (Prod)
+        connectTimeoutMillis = 5_000
         requestTimeoutMillis = 15_000
-        connectTimeoutMillis = 10_000
-        socketTimeoutMillis = 15_000
+        socketTimeoutMillis = 30_000
       }
       install(HttpRequestRetry) {
-        maxRetries = 3
+        maxRetries = 2
         retryIf { _, response -> response.status.value.let { it == 0 || it >= 500 } }
         exponentialDelay()
       }
       defaultRequest {
         url(NetworkConfig.baseUrl.trimEnd('/'))
       }
-      install(Logging) {
-        logger = object : Logger {
-          override fun log(message: String) {
-            println("[apiClient] $message")
-          }
-        }
-        level = LogLevel.INFO
-      }
+      install(Logging) { logger = Logger.SIMPLE; level = LogLevel.NONE }
     }.also { client ->
       // Bearer-Token pro Request dynamisch injizieren (lazy, damit kein Circular-Dependency)
       client.plugin(HttpSend).intercept { request ->