fix: trigger loadAccounts() on auth and loadCachedSchedule() on account selection

The schedule screen was never loading data because no LaunchedEffect
called loadAccounts() when the user became authenticated. Now:
- App.kt: calls scheduleViewModel.loadAccounts() when authState becomes Authenticated
- ScheduleScreen.kt: calls loadCachedSchedule() when selectedAccount is set

composeApp/src/commonMain/kotlin/ch/parano/myice/App.kt

@@ -54,6 +54,9 @@ fun App(
             is AuthState.Unauthenticated -> Screen.Login
             AuthState.Loading -> currentScreen
         }
+        if (authState is AuthState.Authenticated) {
+            scheduleViewModel.loadAccounts()
+        }
     }
 
     MyIceTheme {

composeApp/src/commonMain/kotlin/ch/parano/myice/ui/screens/ScheduleScreen.kt

@@ -17,6 +17,7 @@ import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.ui.Alignment
@@ -44,6 +45,12 @@ fun ScheduleScreen(
     val scheduleState by scheduleViewModel.state.collectAsState()
     val authState by authViewModel.state.collectAsState()
 
+    LaunchedEffect(scheduleState.selectedAccount) {
+        if (scheduleState.selectedAccount != null && scheduleState.events.isEmpty()) {
+            scheduleViewModel.loadCachedSchedule()
+        }
+    }
+
     Scaffold(
         topBar = {
             TopAppBar(