feat(android,ios): open the library the way it was last sorted

Sort order and franchise folding reset on every launch on both phones.
They are kept with the front end's own settings now, and Android reads
them before the first grid is drawn, off the main thread.

android/app/src/main/java/io/narl/protonstream/settings/SettingsStore.kt

@@ -1,6 +1,7 @@
 package io.narl.protonstream.settings
 
 import android.content.Context
+import androidx.core.content.edit
 
 /**
  * The settings that are Android's alone.
@@ -35,6 +36,16 @@ class SettingsStore(context: Context) {
         get() = preferences.getInt(KEY_CACHE_BUDGET_GIB, DEFAULT_CACHE_BUDGET_GIB)
         set(value) { preferences.edit().putInt(KEY_CACHE_BUDGET_GIB, value).apply() }
 
+    /** How the library was last sorted, as a `LibrarySort` name; null for the default. */
+    var librarySort: String?
+        get() = preferences.getString(KEY_LIBRARY_SORT, null)
+        set(value) { preferences.edit { putString(KEY_LIBRARY_SORT, value) } }
+
+    /** Whether the library folds each franchise into one tile. */
+    var libraryGrouped: Boolean
+        get() = preferences.getBoolean(KEY_LIBRARY_GROUPED, true)
+        set(value) { preferences.edit { putBoolean(KEY_LIBRARY_GROUPED, value) } }
+
     companion object {
         /** The desktop's range, in the steps a phone's storage is bought in. */
         val CACHE_BUDGET_CHOICES = listOf(1, 2, 4, 8, 16)
@@ -49,5 +60,7 @@ class SettingsStore(context: Context) {
         private const val KEY_BACKGROUND_AUDIO = "background_audio"
         private const val KEY_HARDWARE_DECODING = "hardware_decoding"
         private const val KEY_CACHE_BUDGET_GIB = "cache_budget_gib"
+        private const val KEY_LIBRARY_SORT = "library_sort"
+        private const val KEY_LIBRARY_GROUPED = "library_grouped"
     }
 }

android/app/src/main/java/io/narl/protonstream/ui/AppViewModel.kt

@@ -25,6 +25,7 @@ import kotlinx.coroutines.flow.callbackFlow
 import kotlinx.coroutines.channels.awaitClose
 import kotlinx.coroutines.withContext
 import io.narl.protonstream.native.NativeRuntime
+import io.narl.protonstream.settings.SettingsStore
 import io.narl.protonstream.ui.theme.AppearanceState
 import uniffi.pstr_android.ArrangementRecord
 import uniffi.pstr_android.LibrarySort
@@ -123,7 +124,17 @@ class AppViewModel(context: Context, private val workManager: WorkManager) : Vie
                 it.copy(message = "Certificate verification is unavailable; Proton requests will fail")
             }
         }
-        reload()
+        // The arrangement first, so the first grid is drawn the way the viewer
+        // left it rather than A–Z and then re-sorted under them.
+        viewModelScope.launch {
+            val (sort, grouped) = withContext(Dispatchers.IO) {
+                SettingsStore(appContext).run {
+                    librarySort?.let { name -> LibrarySort.entries.firstOrNull { it.name == name } } to libraryGrouped
+                }
+            }
+            mutableState.update { it.copy(sort = sort ?: it.sort, grouped = grouped) }
+            reload()
+        }
         catchUp()
         viewModelScope.launch {
             val account = runCatching { withContext(Dispatchers.IO) { NativeRuntime.engine().accountState() } }
@@ -153,9 +164,18 @@ class AppViewModel(context: Context, private val workManager: WorkManager) : Vie
     }
 
     /** Reorder the grid, or fold or unfold its franchises. */
+    /** Sort and fold the library, and keep both for the next launch. */
     fun arrange(sort: LibrarySort, grouped: Boolean) {
         mutableState.update { it.copy(sort = sort, grouped = grouped) }
-        viewModelScope.launch { reloadLibrary(mutableState.value.query) }
+        viewModelScope.launch {
+            withContext(Dispatchers.IO) {
+                SettingsStore(appContext).apply {
+                    librarySort = sort.name
+                    libraryGrouped = grouped
+                }
+            }
+            reloadLibrary(mutableState.value.query)
+        }
     }
 
     fun search(query: String) {