fix(settings): retain config session across navigation

androidApp/src/main/kotlin/org/meshtastic/app/ui/Main.kt

@@ -54,6 +54,7 @@ import org.meshtastic.feature.map.navigation.mapGraph
 import org.meshtastic.feature.messaging.navigation.contactsGraph
 import org.meshtastic.feature.node.navigation.nodesGraph
 import org.meshtastic.feature.settings.lockdown.LockdownDialog
+import org.meshtastic.feature.settings.navigation.rememberSettingsRadioConfigViewModelProvider
 import org.meshtastic.feature.settings.navigation.settingsGraph
 import org.meshtastic.feature.settings.radio.channel.channelsGraph
 import org.meshtastic.feature.wifiprovision.navigation.wifiProvisionGraph
@@ -62,16 +63,11 @@ import org.meshtastic.feature.wifiprovision.navigation.wifiProvisionGraph
 fun MainScreen() {
     val viewModel: UIViewModel = koinViewModel()
     // Land on Connections for first-run / no-device-selected; otherwise on Nodes (seeded from prefs).
-    val initialTab = remember {
-        if (viewModel.currentDeviceAddressFlow.value.isNullOrSelectedNone()) {
-            TopLevelDestination.Connect.route
-        } else {
-            NodesRoute.Nodes
-        }
-    }
+    val initialTab = remember { initialRoute(viewModel.currentDeviceAddressFlow.value) }
     val multiBackstack = rememberMultiBackstack(initialTab)
     val backStack = multiBackstack.activeBackStack
     val scrollToTopEvents = viewModel.scrollToTopEventFlow
+    val settingsRadioConfigViewModelProvider = rememberSettingsRadioConfigViewModelProvider(backStack)
 
     AndroidAppVersionCheck(viewModel)
 
@@ -113,7 +109,7 @@ fun MainScreen() {
                     channelsGraph(backStack)
                     connectionsGraph(backStack)
                     discoveryGraph(backStack)
-                    settingsGraph(backStack)
+                    settingsGraph(backStack, settingsRadioConfigViewModelProvider)
                     docsEntries(backStack)
                     firmwareGraph(backStack)
                     wifiProvisionGraph(backStack)
@@ -125,6 +121,9 @@ fun MainScreen() {
     }
 }
 
+private fun initialRoute(deviceAddress: String?): NavKey =
+    if (deviceAddress.isNullOrSelectedNone()) TopLevelDestination.Connect.route else NodesRoute.Nodes
+
 /** True when no device address is persisted, or the address is the "none" sentinel (`"n"`). */
 private fun String?.isNullOrSelectedNone(): Boolean = isNullOrBlank() || this == "n"
 

androidApp/src/test/kotlin/org/meshtastic/app/ui/NavigationAssemblyTest.kt

@@ -54,7 +54,7 @@ class NavigationAssemblyTest {
                 channelsGraph(backStack)
                 connectionsGraph(backStack)
                 discoveryGraph(backStack)
-                settingsGraph(backStack)
+                settingsGraph(backStack) { _ -> error("Settings ViewModel is not composed in this assembly test") }
                 firmwareGraph(backStack)
             }
         }

desktopApp/src/main/kotlin/org/meshtastic/desktop/navigation/DesktopNavigation.kt

@@ -16,10 +16,12 @@
  */
 package org.meshtastic.desktop.navigation
 
+import androidx.compose.runtime.Composable
 import androidx.navigation3.runtime.EntryProviderScope
 import androidx.navigation3.runtime.NavBackStack
 import androidx.navigation3.runtime.NavKey
 import org.meshtastic.core.navigation.MultiBackstack
+import org.meshtastic.core.navigation.SettingsRoute
 import org.meshtastic.core.navigation.TopLevelDestination
 import org.meshtastic.core.ui.viewmodel.UIViewModel
 import org.meshtastic.feature.connections.navigation.connectionsGraph
@@ -30,6 +32,7 @@ import org.meshtastic.feature.map.navigation.mapGraph
 import org.meshtastic.feature.messaging.navigation.contactsGraph
 import org.meshtastic.feature.node.navigation.nodesGraph
 import org.meshtastic.feature.settings.navigation.settingsGraph
+import org.meshtastic.feature.settings.radio.RadioConfigViewModel
 import org.meshtastic.feature.settings.radio.channel.channelsGraph
 import org.meshtastic.feature.wifiprovision.navigation.wifiProvisionGraph
 
@@ -43,6 +46,7 @@ fun EntryProviderScope<NavKey>.desktopNavGraph(
     backStack: NavBackStack<NavKey>,
     uiViewModel: UIViewModel,
     multiBackstack: MultiBackstack,
+    settingsRadioConfigViewModel: @Composable (SettingsRoute.Settings?) -> RadioConfigViewModel,
 ) {
     nodesGraph(
         backStack = backStack,
@@ -57,7 +61,7 @@ fun EntryProviderScope<NavKey>.desktopNavGraph(
     )
     mapGraph(backStack)
     firmwareGraph(backStack)
-    settingsGraph(backStack)
+    settingsGraph(backStack, settingsRadioConfigViewModel)
     docsEntries(backStack)
     channelsGraph(backStack)
     connectionsGraph(backStack)

desktopApp/src/main/kotlin/org/meshtastic/desktop/ui/DesktopMainScreen.kt

@@ -30,16 +30,19 @@ import org.meshtastic.core.ui.component.MeshtasticNavDisplay
 import org.meshtastic.core.ui.component.MeshtasticNavigationSuite
 import org.meshtastic.core.ui.viewmodel.UIViewModel
 import org.meshtastic.desktop.navigation.desktopNavGraph
+import org.meshtastic.feature.settings.navigation.rememberSettingsRadioConfigViewModelProvider
 
 /**
  * Desktop main screen — assembles the shared [MeshtasticAppShell], [MeshtasticNavigationSuite], and
  * [MeshtasticNavDisplay] with the desktop-specific [desktopNavGraph] entry provider.
  */
+@Suppress("ViewModelForwarding")
 @Composable
-fun DesktopMainScreen(uiViewModel: UIViewModel, multiBackstack: MultiBackstack) {
+fun DesktopMainScreen(uiViewModel: UIViewModel, multiBackstack: MultiBackstack, modifier: Modifier = Modifier) {
     val backStack = multiBackstack.activeBackStack
+    val settingsRadioConfigViewModelProvider = rememberSettingsRadioConfigViewModelProvider(backStack)
 
-    Surface(modifier = Modifier.fillMaxSize()) {
+    Surface(modifier = modifier.fillMaxSize()) {
         MeshtasticAppShell(
             multiBackstack = multiBackstack,
             uiViewModel = uiViewModel,
@@ -50,7 +53,15 @@ fun DesktopMainScreen(uiViewModel: UIViewModel, multiBackstack: MultiBackstack)
                 uiViewModel = uiViewModel,
                 modifier = Modifier.fillMaxSize(),
             ) {
-                val provider = entryProvider<NavKey> { desktopNavGraph(backStack, uiViewModel, multiBackstack) }
+                val provider =
+                    entryProvider<NavKey> {
+                        desktopNavGraph(
+                            backStack = backStack,
+                            uiViewModel = uiViewModel,
+                            multiBackstack = multiBackstack,
+                            settingsRadioConfigViewModel = settingsRadioConfigViewModelProvider,
+                        )
+                    }
                 MeshtasticNavDisplay(
                     multiBackstack = multiBackstack,
                     entryProvider = provider,