feat: select school terms and smooth refractive Dock motion

mobile/test/data/json_schedule_import_test.dart

@@ -3,6 +3,10 @@ import 'dart:convert';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:hepan_everyday/data/json_schedule_import.dart';
 import 'package:hepan_everyday/domain/course.dart';
+import 'package:hepan_everyday/domain/app_snapshot.dart';
+import 'package:hepan_everyday/domain/school_term.dart';
+
+import '../domain/schedule_engine_test.dart' show course;
 
 Map<String, dynamic> row({String id = 'a', int day = 1}) => {
   'id': id,
@@ -17,6 +21,27 @@ Map<String, dynamic> row({String id = 'a', int day = 1}) => {
 String input(List<dynamic> courses, {int version = 1, bool demo = false}) =>
     jsonEncode({'schemaVersion': version, 'isDemo': demo, 'courses': courses});
 void main() {
+  test('saved term metadata and legacy course IDs keep JSON imports in their actual term', () {
+    final saved = AppSnapshot(
+      schoolTerm: SchoolTerm(72),
+      courses: [course()],
+    ).toJson();
+    expect(
+      JsonScheduleImport.parse(jsonEncode(saved)).schoolTerm,
+      SchoolTerm(72),
+    );
+    saved.remove('schoolTerm');
+    (saved['courses'] as List).first['id'] = 'uestc-71-101-1-1-2-example';
+    expect(
+      JsonScheduleImport.parse(jsonEncode(saved)).schoolTerm,
+      SchoolTerm(71),
+    );
+    saved['schoolTerm'] = {'id': 0};
+    expect(
+      () => JsonScheduleImport.parse(jsonEncode(saved)),
+      throwsFormatException,
+    );
+  });
   test('file import normalizes weeks and cannot claim school provenance', () {
     final parsed = JsonScheduleImport.parse(input([row()]));
     expect(parsed.courses, hasLength(1));