fix: clean up orphaned and partial files after cancelled downloads

Treat inactive download contexts as cancellation, delete the partial file, and
rethrow the cancellation so the pipeline does not retain an incomplete payload.
Also remove orphaned .dsl/.dz files left behind by cancelled downloads.
Run the partial/orphan deletions on NonCancellable: the cleanup is invoked from
already-cancelled coroutines, where withContext(Dispatchers.IO) aborts before
executing the block and silently leaves the files behind.

app/src/main/java/com/example/research/MainActivity.kt

@@ -26,6 +26,7 @@ import com.example.research.common.ui.AppLocaleProvider
 import com.example.research.common.ui.BackgroundTextMeasurementProvider
 import com.example.research.common.ui.theme.ReSearchTheme
 import com.example.research.core.domain.model.AppTheme
+import com.example.research.data.local.preferences.SectionExpansionStates
 import com.example.research.feature.search.SearchAction
 import com.example.research.feature.search.SearchViewModel
 import com.example.research.ui.navigation.AppNavigation
@@ -51,6 +52,8 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    private var initialSectionExpansion: SectionExpansionStates? = null
+
     private val settingsViewModel: SettingsViewModel by viewModels {
         val app = application as ReSearchApplication
         val versionName = try {
@@ -69,6 +72,11 @@ class MainActivity : ComponentActivity() {
                     app.dictionaryImportManager,
                     app.dictionaryProgressStateHolder,
                     versionName,
+                    initialSectionExpansion ?: SectionExpansionStates(
+                        isThemeExpanded = false,
+                        isLanguageExpanded = false,
+                        isDictionariesExpanded = true,
+                    ),
                 )
             }
         }
@@ -84,6 +92,7 @@ class MainActivity : ComponentActivity() {
         val initialTheme = loadInitialTheme(app)
         val initialLanguage = loadInitialLanguage(app)
         val initialHadNoDictionaries = loadInitialHadNoDictionaries(app)
+        initialSectionExpansion = loadInitialSectionExpansion(app)
 
         handleIntent(intent)
         setContent {
@@ -177,6 +186,21 @@ class MainActivity : ComponentActivity() {
         }
     }
 
+    private fun loadInitialSectionExpansion(app: ReSearchApplication): SectionExpansionStates {
+        return try {
+            runBlocking {
+                app.preferencesManager.sectionExpansionStates()
+            }
+        } catch (e: Exception) {
+            android.util.Log.e("MainActivity", "Failed to load section expansion states: ${e.message}")
+            SectionExpansionStates(
+                isThemeExpanded = false,
+                isLanguageExpanded = false,
+                isDictionariesExpanded = true,
+            )
+        }
+    }
+
     override fun onNewIntent(intent: Intent) {
         super.onNewIntent(intent)
         handleIntent(intent)

app/src/main/java/com/example/research/data/local/preferences/PreferencesManager.kt

@@ -10,12 +10,19 @@ import androidx.datastore.preferences.core.stringSetPreferencesKey
 import androidx.datastore.preferences.preferencesDataStore
 import com.example.research.core.domain.model.DictionarySource
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.map
 import kotlinx.serialization.json.Json
 import java.io.File
 
 private val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "settings")
 
+data class SectionExpansionStates(
+    val isThemeExpanded: Boolean,
+    val isLanguageExpanded: Boolean,
+    val isDictionariesExpanded: Boolean,
+)
+
 class PreferencesManager(private val context: Context) {
     private object PreferencesKeys {
         val THEME_MODE = stringPreferencesKey("theme_mode")
@@ -79,6 +86,15 @@ class PreferencesManager(private val context: Context) {
         }
     }
 
+    suspend fun sectionExpansionStates(): SectionExpansionStates =
+        context.dataStore.data.first().let { preferences ->
+            SectionExpansionStates(
+                isThemeExpanded = preferences[PreferencesKeys.IS_THEME_EXPANDED] ?: false,
+                isLanguageExpanded = preferences[PreferencesKeys.IS_LANGUAGE_EXPANDED] ?: false,
+                isDictionariesExpanded = preferences[PreferencesKeys.IS_DICTIONARIES_EXPANDED] ?: true,
+            )
+        }
+
     suspend fun setDictionaryActive(path: String, isActive: Boolean) {
         context.dataStore.edit { preferences ->
             val disabledPaths = preferences[PreferencesKeys.DISABLED_DICTIONARY_PATHS]

app/src/main/java/com/example/research/ui/settings/SettingsViewModel.kt

@@ -16,6 +16,7 @@ import com.example.research.core.domain.usecase.DictionarySourceValidator
 import com.example.research.core.domain.usecase.ManageDictionarySourcesUseCase
 import com.example.research.core.util.OperationResult
 import com.example.research.data.local.preferences.PreferencesManager
+import com.example.research.data.local.preferences.SectionExpansionStates
 import com.example.research.data.repository.LocalDictionaryRepository
 import com.example.research.feature.download.DownloadManager
 import com.example.research.feature.download.model.DownloadState
@@ -61,6 +62,7 @@ class SettingsViewModel(
     private val dictionaryImportManager: DictionaryImportManager,
     progressStateHolder: DictionaryProgressStateHolder,
     appVersion: String,
+    initialSectionExpansion: SectionExpansionStates,
 ) : AndroidViewModel(application) {
 
     private val manageDictionarySourcesUseCase = ManageDictionarySourcesUseCase(
@@ -68,7 +70,14 @@ class SettingsViewModel(
         validator = DictionarySourceValidator(),
     )
 
-    private val _uiState = MutableStateFlow(SettingsUiState(appVersion = appVersion))
+    private val _uiState = MutableStateFlow(
+        SettingsUiState(
+            appVersion = appVersion,
+            isThemeExpanded = initialSectionExpansion.isThemeExpanded,
+            isLanguageExpanded = initialSectionExpansion.isLanguageExpanded,
+            isDictionariesExpanded = initialSectionExpansion.isDictionariesExpanded,
+        )
+    )
     val uiState: StateFlow<SettingsUiState> = _uiState.asStateFlow()
 
     val progressSnapshot = progressStateHolder.progressSnapshot