fix: share ConfigViewModel via nested NavGraph to prevent infinite spinner

List and Detail screens were creating separate ViewModel instances, causing
a race condition where Detail's schema was always null. Using a nested
navigation graph scopes a single ViewModel to the parent back stack entry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

android/app/src/main/java/io/clawdroid/MainActivity.kt

@@ -9,18 +9,22 @@ import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.core.content.ContextCompat
+import androidx.compose.runtime.remember
 import androidx.navigation.NavType
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
+import androidx.navigation.compose.navigation
 import androidx.navigation.compose.rememberNavController
 import androidx.navigation.navArgument
 import io.clawdroid.backend.config.ConfigSectionDetailScreen
 import io.clawdroid.backend.config.ConfigSectionListScreen
+import io.clawdroid.backend.config.ConfigViewModel
 import io.clawdroid.core.ui.theme.ClawDroidTheme
 import io.clawdroid.feature.chat.screen.ChatScreen
 import io.clawdroid.feature.chat.screen.SettingsScreen
 import io.clawdroid.navigation.NavRoutes
 import io.clawdroid.settings.AppSettingsScreen
+import org.koin.androidx.compose.koinViewModel
 
 class MainActivity : ComponentActivity() {
 
@@ -48,23 +52,38 @@ class MainActivity : ComponentActivity() {
                             onNavigateToAppSettings = { navController.navigate(NavRoutes.APP_SETTINGS) },
                         )
                     }
-                    composable(NavRoutes.BACKEND_SETTINGS) {
+                    navigation(
+                        route = NavRoutes.BACKEND_SETTINGS,
+                        startDestination = NavRoutes.BACKEND_SETTINGS_LIST,
+                    ) {
+                        composable(NavRoutes.BACKEND_SETTINGS_LIST) { entry ->
+                            val parentEntry = remember(entry) {
+                                navController.getBackStackEntry(NavRoutes.BACKEND_SETTINGS)
+                            }
+                            val viewModel: ConfigViewModel = koinViewModel(viewModelStoreOwner = parentEntry)
                             ConfigSectionListScreen(
                                 onNavigateBack = { navController.popBackStack() },
                                 onSectionSelected = { sectionKey ->
                                     navController.navigate("backend_settings/$sectionKey")
                                 },
+                                viewModel = viewModel,
                             )
                         }
                         composable(
                             NavRoutes.BACKEND_SETTINGS_SECTION,
                             arguments = listOf(navArgument("sectionKey") { type = NavType.StringType }),
-                    ) { backStackEntry ->
+                        ) { entry ->
+                            val parentEntry = remember(entry) {
+                                navController.getBackStackEntry(NavRoutes.BACKEND_SETTINGS)
+                            }
+                            val viewModel: ConfigViewModel = koinViewModel(viewModelStoreOwner = parentEntry)
                             ConfigSectionDetailScreen(
-                            sectionKey = backStackEntry.arguments?.getString("sectionKey") ?: "",
+                                sectionKey = entry.arguments?.getString("sectionKey") ?: "",
                                 onNavigateBack = { navController.popBackStack() },
+                                viewModel = viewModel,
                             )
                         }
+                    }
                     composable(NavRoutes.APP_SETTINGS) {
                         AppSettingsScreen(
                             onNavigateBack = { navController.popBackStack() },

android/app/src/main/java/io/clawdroid/navigation/NavRoutes.kt

@@ -4,6 +4,7 @@ object NavRoutes {
     const val CHAT = "chat"
     const val SETTINGS = "settings"
     const val BACKEND_SETTINGS = "backend_settings"
+    const val BACKEND_SETTINGS_LIST = "backend_settings/list"
     const val BACKEND_SETTINGS_SECTION = "backend_settings/{sectionKey}"
     const val APP_SETTINGS = "app_settings"
 }

android/backend/config/src/main/java/io/clawdroid/backend/config/ConfigSectionDetailScreen.kt

@@ -59,14 +59,13 @@ import io.clawdroid.core.ui.theme.NeonCyan
 import io.clawdroid.core.ui.theme.TextPrimary
 import io.clawdroid.core.ui.theme.TextSecondary
 import kotlinx.coroutines.launch
-import org.koin.androidx.compose.koinViewModel
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun ConfigSectionDetailScreen(
     sectionKey: String,
     onNavigateBack: () -> Unit,
-    viewModel: ConfigViewModel = koinViewModel(),
+    viewModel: ConfigViewModel,
 ) {
     val uiState by viewModel.uiState.collectAsState()
     val snackbarHostState = remember { SnackbarHostState() }

android/backend/config/src/main/java/io/clawdroid/backend/config/ConfigSectionListScreen.kt

@@ -42,14 +42,13 @@ import io.clawdroid.core.ui.theme.GlassWhite
 import io.clawdroid.core.ui.theme.NeonCyan
 import io.clawdroid.core.ui.theme.TextPrimary
 import io.clawdroid.core.ui.theme.TextSecondary
-import org.koin.androidx.compose.koinViewModel
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun ConfigSectionListScreen(
     onNavigateBack: () -> Unit,
     onSectionSelected: (sectionKey: String) -> Unit,
-    viewModel: ConfigViewModel = koinViewModel(),
+    viewModel: ConfigViewModel,
 ) {
     val uiState by viewModel.uiState.collectAsState()