feat: select school terms and smooth refractive Dock motion

mobile/lib/data/json_schedule_import.dart

@@ -1,4 +1,5 @@
 import '../domain/course.dart';
+import '../domain/school_term.dart';
 
 import 'dart:convert';
 
@@ -9,12 +10,14 @@ class ImportDraft {
     required this.source,
     required this.parserVersion,
     this.semesterLabel,
+    this.schoolTerm,
   });
   final List<Course> courses;
   final bool explicitlyEmpty;
   final CourseSource source;
   final String parserVersion;
   final String? semesterLabel;
+  final SchoolTerm? schoolTerm;
 }
 
 class JsonScheduleImport {
@@ -46,11 +49,28 @@ class JsonScheduleImport {
       if (courses.map((c) => c.id).toSet().length != courses.length) {
         throw const FormatException('课程标识重复');
       }
+      final termIds = courses
+          .map((c) => RegExp(r'^uestc-(\d+)-').firstMatch(c.id)?.group(1))
+          .whereType<String>()
+          .toSet();
+      final term = json['schoolTerm'] != null
+          ? SchoolTerm.fromJson(
+              Map<String, dynamic>.from(json['schoolTerm'] as Map),
+            )
+          : termIds.length == 1
+          ? SchoolTerm(int.parse(termIds.single))
+          : null;
+      if (termIds.length > 1 ||
+          (term != null && termIds.any((id) => id != term.id.toString()))) {
+        throw const FormatException('文件中包含不同学期的课程');
+      }
       return ImportDraft(
         courses: List.unmodifiable(courses),
         explicitlyEmpty: json['explicitlyEmpty'] == true,
         source: source,
         parserVersion: 'json-v1',
+        schoolTerm: source == CourseSource.demo ? null : term,
+        semesterLabel: term?.label,
       );
     } on FormatException {
       rethrow;