feat: 动态未读标记 issues #459

lib/models/common/dynamic_badge_mode.dart

@@ -0,0 +1,9 @@
+enum DynamicBadgeMode { hidden, point, number }
+
+extension DynamicBadgeModeDesc on DynamicBadgeMode {
+  String get description => ['隐藏', '红点', '数字'][index];
+}
+
+extension DynamicBadgeModeCode on DynamicBadgeMode {
+  int get code => [0, 1, 2][index];
+}