fix(ui): keep username draft stable while editing

shared/src/commonMain/kotlin/com/vnidrop/app/feature/settings/SettingsViewModel.kt

@@ -101,18 +101,16 @@ class SettingsViewModel(
 	val effectFlow = effects.receiveAsFlow()
 	private var enableNotificationsAfterSettings = false
 	private var usernamePersistJob: Job? = null
+	private var hasLocalUsernameDraft = false
 
 	init {
 		viewModelScope.launch {
 			preferencesRepository.preferences.collect { preferences ->
 				val previousFolder = _state.value.receiveFolder
 				val receiveFolder = fileSystemService.effectiveReceiveFolder(preferences.receiveFolder)
-				// While the user is typing, keep the in-progress value. DataStore
-				// echoes can race keystrokes and trim trailing spaces mid-edit.
-				val editingUsername = usernamePersistJob?.isActive == true
 				_state.update { current ->
 					current.copy(
-						username = if (editingUsername) current.username else preferences.username,
+						username = if (hasLocalUsernameDraft) current.username else preferences.username,
 						receiveFolder = receiveFolder,
 						themeMode = preferences.themeMode,
 						notificationsEnabled = preferences.notificationsEnabled,
@@ -140,6 +138,7 @@ class SettingsViewModel(
 	}
 
 	fun setUsername(value: String) {
+		hasLocalUsernameDraft = true
 		_state.update { it.copy(username = value) }
 		usernamePersistJob?.cancel()
 		usernamePersistJob = viewModelScope.launch {

shared/src/commonTest/kotlin/com/vnidrop/app/feature/ViewModelsTest.kt

@@ -90,7 +90,7 @@ class ViewModelsTest {
 	}
 
 	@Test
-	fun settingsUsernameKeepsSpacesWhileTypingAndPersistsAfterDebounce() = runTest {
+	fun settingsUsernameDraftIsNotOverwrittenByPersistedEcho() = runTest {
 		Dispatchers.setMain(StandardTestDispatcher(testScheduler))
 		val preferences = preferences()
 		val viewModel = settingsViewModel(preferences)
@@ -104,7 +104,11 @@ class ViewModelsTest {
 		testScheduler.advanceTimeBy(400)
 		advanceUntilIdle()
 		assertEquals("Ada", preferences.mutablePreferences.value.username)
-		assertEquals("Ada", viewModel.state.value.username)
+		assertEquals("Ada ", viewModel.state.value.username)
+
+		preferences.setThemeMode(ThemeMode.Dark)
+		advanceUntilIdle()
+		assertEquals("Ada ", viewModel.state.value.username)
 	}
 
 	@Test