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.

ios/ProtonStream/App/AppModel.swift

@@ -44,8 +44,9 @@ final class AppModel {
     /// `grouped`, and the shelves above it. Nil until the bridge has answered,
     /// when the grid falls back to `titles` as they are.
     var arrangement: ArrangementRecord?
-    var sort: LibrarySort = .name
-    var grouped = true
+    /// As the viewer last left them.
+    var sort: LibrarySort = SettingsStore().librarySort
+    var grouped = SettingsStore().libraryGrouped
     var shares: [ShareRecord] = []
     var offline: [OfflineRecord] = []
     var metadataSettings = MetadataSettingsRecord(enabled: false, provider: .aniList, language: "en", ready: true)
@@ -105,6 +106,9 @@ final class AppModel {
     func arrange(_ sort: LibrarySort, _ grouped: Bool) {
         self.sort = sort
         self.grouped = grouped
+        let settings = SettingsStore()
+        settings.librarySort = sort
+        settings.libraryGrouped = grouped
         Task { await reloadLibrary(query) }
     }
 

ios/ProtonStream/App/SettingsStore.swift

@@ -42,6 +42,23 @@ struct SettingsStore {
 
     static func gibToBytes(_ gib: Int) -> UInt64 { UInt64(gib) * 1024 * 1024 * 1024 }
 
+    /// How the library was last sorted; `.name` until the viewer chooses.
+    var librarySort: LibrarySort {
+        get {
+            let stored = defaults.string(forKey: Key.librarySort)
+            return Self.sorts.first { String(describing: $0) == stored } ?? .name
+        }
+        nonmutating set { defaults.set(String(describing: newValue), forKey: Key.librarySort) }
+    }
+
+    /// Whether the library folds each franchise into one tile.
+    var libraryGrouped: Bool {
+        get { bool(Key.libraryGrouped, default: true) }
+        nonmutating set { defaults.set(newValue, forKey: Key.libraryGrouped) }
+    }
+
+    private static let sorts: [LibrarySort] = [.name, .recent, .added, .release, .rating, .popularity]
+
     private func bool(_ key: String, default value: Bool) -> Bool {
         defaults.object(forKey: key) as? Bool ?? value
     }
@@ -51,5 +68,7 @@ struct SettingsStore {
         static let backgroundAudio = "background_audio"
         static let hardwareDecoding = "hardware_decoding"
         static let cacheBudgetGib = "cache_budget_gib"
+        static let librarySort = "library_sort"
+        static let libraryGrouped = "library_grouped"
     }
 }