refactor to per row store

mobile/lib/domain/models/metadata_key.dart

@@ -0,0 +1,31 @@
+import 'package:flutter/material.dart';
+import 'package:immich_mobile/domain/models/log.model.dart';
+
+enum MetadataDomain {
+  appConfig('app-config'),
+  systemConfig('system-config');
+
+  final String prefix;
+  const MetadataDomain(this.prefix);
+}
+
+enum MetadataKey<T extends Object> {
+  themeMode<ThemeMode>(.appConfig, 'theme.mode', .system, ThemeMode.values),
+  logLevel<LogLevel>(.systemConfig, 'log.level', .info, LogLevel.values);
+
+  final MetadataDomain domain;
+  final String name;
+  final T defaultValue;
+  final List<T>? enumValues;
+
+  const MetadataKey(this.domain, this.name, this.defaultValue, [this.enumValues]);
+
+  String get key => '${domain.prefix}.$name';
+
+  static MetadataKey<Object>? fromKey(String key) {
+    for (final m in MetadataKey.values) {
+      if (m.key == key) return m;
+    }
+    return null;
+  }
+}