feat: implement per book settings with player configuration and update methods

lib/features/per_book_settings/providers/book_settings_provider.dart

@@ -0,0 +1,57 @@
+import 'package:logging/logging.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+import 'package:vaani/db/available_boxes.dart';
+import 'package:vaani/features/per_book_settings/models/book_settings.dart'
+    as model;
+import 'package:vaani/features/per_book_settings/models/nullable_player_settings.dart';
+
+part 'book_settings_provider.g.dart';
+
+final _box = AvailableHiveBoxes.individualBookSettingsBox;
+
+final _logger = Logger('BookSettingsProvider');
+
+model.BookSettings readFromBoxOrCreate(String bookId) {
+  final foundSettings = _box.get(bookId);
+  if (foundSettings != null) {
+    _logger.fine('found book settings for $bookId in box: $foundSettings');
+    return foundSettings;
+  } else {
+    // create a new settings object
+    final settings = model.BookSettings(
+      bookId: bookId,
+      playerSettings: const NullablePlayerSettings(),
+    );
+    _logger.fine('created new book settings for $bookId: $settings');
+    writeToBox(settings);
+    return settings;
+  }
+}
+
+void writeToBox(model.BookSettings newSettings) {
+  _box.put(newSettings.bookId, newSettings);
+  _logger.fine(
+    'wrote book settings for ${newSettings.bookId} to box: $newSettings',
+  );
+}
+
+void updateState(model.BookSettings newSettings, {bool force = false}) {
+  // check if the settings are different
+  final foundSettings = _box.get(newSettings.bookId);
+  if (foundSettings == newSettings && !force) {
+    return;
+  }
+  writeToBox(newSettings);
+}
+
+@riverpod
+class BookSettings extends _$BookSettings {
+  @override
+  model.BookSettings build(String bookId) {
+    return readFromBoxOrCreate(bookId);
+  }
+
+  void update(model.BookSettings newSettings, {bool force = false}) {
+    updateState(newSettings, force: force);
+  }
+}