feat: add Ktor networking layer with ApiService and auth token holder

Add ApiConfig, AuthTokenHolder singleton, expect/actual HttpClient
engine factories (CIO for Android/Desktop, Darwin for iOS), and
ApiService with four GET endpoints. Bearer token from AuthTokenHolder
is injected as Authorization header on each request.

Adjusted for Ktor 3.5.1: HttpClientEngineFactory lives in
io.ktor.client.engine; the timeout plugin is HttpTimeout (package
io.ktor.client.plugins), not HttpTimeoutPlugin. Tests wrap suspend
calls in runTest and assert request URLs without a trailing '?'.

composeApp/src/commonMain/kotlin/ch/parano/myice/network/ApiConfig.kt

@@ -0,0 +1,5 @@
+package ch.parano.myice.network
+
+object ApiConfig {
+    const val baseUrl = "https://myice.parano.ch"
+}

composeApp/src/commonMain/kotlin/ch/parano/myice/network/ApiEngine.kt

@@ -0,0 +1,23 @@
+package ch.parano.myice.network
+
+import io.ktor.client.HttpClient
+import io.ktor.client.engine.HttpClientEngineConfig
+import io.ktor.client.engine.HttpClientEngineFactory
+import io.ktor.client.plugins.contentnegotiation.ContentNegotiation
+import io.ktor.client.plugins.HttpTimeout
+import io.ktor.serialization.kotlinx.json.json
+import kotlinx.serialization.json.Json
+
+expect fun createEngine(): HttpClientEngineFactory<HttpClientEngineConfig>
+
+fun createHttpClient(): HttpClient {
+    return HttpClient(createEngine()) {
+        install(ContentNegotiation) {
+            json(Json { ignoreUnknownKeys = true })
+        }
+        install(HttpTimeout) {
+            connectTimeoutMillis = 10_000
+            requestTimeoutMillis = 10_000
+        }
+    }
+}

composeApp/src/commonMain/kotlin/ch/parano/myice/network/ApiService.kt

@@ -0,0 +1,38 @@
+package ch.parano.myice.network
+
+import ch.parano.myice.models.Account
+import ch.parano.myice.models.Event
+import ch.parano.myice.models.EventDetail
+import ch.parano.myice.models.UserInfo
+import io.ktor.client.HttpClient
+import io.ktor.client.call.body
+import io.ktor.client.request.get
+import io.ktor.client.request.header
+import io.ktor.http.HttpHeaders
+
+class ApiService(private val client: HttpClient) {
+
+    private fun authHeader(): String? = AuthTokenHolder.token?.let { "Bearer $it" }
+
+    suspend fun getUserInfo(): UserInfo =
+        client.get("${ApiConfig.baseUrl}/userinfo") {
+            authHeader()?.let { header(HttpHeaders.Authorization, it) }
+        }.body()
+
+    suspend fun getAccounts(): List<Account> =
+        client.get("${ApiConfig.baseUrl}/accounts") {
+            authHeader()?.let { header(HttpHeaders.Authorization, it) }
+        }.body()
+
+    suspend fun getSchedule(account: String): List<Event> =
+        client.get("${ApiConfig.baseUrl}/schedule") {
+            url.parameters.append("account", account)
+            authHeader()?.let { header(HttpHeaders.Authorization, it) }
+        }.body()
+
+    suspend fun getGameDetail(gameId: String, account: String): EventDetail =
+        client.get("${ApiConfig.baseUrl}/game/$gameId") {
+            url.parameters.append("account", account)
+            authHeader()?.let { header(HttpHeaders.Authorization, it) }
+        }.body()
+}

composeApp/src/commonMain/kotlin/ch/parano/myice/network/AuthTokenHolder.kt

@@ -0,0 +1,5 @@
+package ch.parano.myice.network
+
+object AuthTokenHolder {
+    var token: String? = null
+}