feat: add two-tab timetable UI and glass dock

mobile/lib/data/json_schedule_import.dart

@@ -18,8 +18,9 @@ class ImportDraft {
 class JsonScheduleImport {
   static ImportDraft parse(String text) {
     try {
-      if (utf8.encode(text).length > 2 * 1024 * 1024)
+      if (utf8.encode(text).length > 2 * 1024 * 1024) {
         throw const FormatException('文件不能超过 2 MB');
+      }
       final json = jsonDecode(text);
       if (json is! Map ||
           json['schemaVersion'] != 1 ||
@@ -40,8 +41,9 @@ class JsonScheduleImport {
             ),
           )
           .toList();
-      if (courses.map((c) => c.id).toSet().length != courses.length)
+      if (courses.map((c) => c.id).toSet().length != courses.length) {
         throw const FormatException('课程标识重复');
+      }
       return ImportDraft(
         courses: List.unmodifiable(courses),
         explicitlyEmpty: json['explicitlyEmpty'] == true,