fix: harden school imports and add optional feedback diagnostics

mobile/test/features/feedback_http_sender_test.dart

@@ -33,6 +33,27 @@ class FakeFeedbackHttpTransport implements FeedbackHttpTransport {
 }
 
 void main() {
+  test('diagnostics use a separate UTF8 attachment field', () async {
+    final transport = FakeFeedbackHttpTransport();
+    await HttpFeedbackSender(
+      endpoint: 'https://example.com/v1/feedback',
+      transport: transport,
+    ).send(
+      FeedbackSubmission.problem(
+        id: 'same-id',
+        message: '问题',
+        diagnosticLog: Uint8List.fromList(
+          utf8.encode('TPSchedule diagnostic log\nlogin_opened'),
+        ),
+      ),
+    );
+    final body = utf8.decode(transport.body!);
+    expect(
+      body,
+      contains('name="diagnostics"; filename="TPSchedule-diagnostics.txt"'),
+    );
+    expect(body, contains('login_opened'));
+  });
   test(
     'matching uncertain delivery is distinct and never exposes server detail',
     () async {

mobile/test/features/feedback_test.dart

@@ -31,10 +31,29 @@ Future<void> reveal(
     backwards ? -250 : 250,
     scrollable: find.byType(Scrollable).first,
   );
-  await tester.pump();
+  await tester.pumpAndSettle();
 }
 
 void main() {
+  testWidgets('logs are opt in and included only when checked', (tester) async {
+    final sender = RecordingSender();
+    await tester.pumpWidget(MaterialApp(home: FeedbackPage(sender: sender)));
+    await tester.enterText(find.byKey(const Key('feedback-message')), '无法登录');
+    await reveal(tester, find.byKey(const Key('feedback-logs')));
+    expect(
+      tester
+          .widget<CheckboxListTile>(find.byKey(const Key('feedback-logs')))
+          .value,
+      isFalse,
+    );
+    await tester.tap(find.byKey(const Key('feedback-logs')));
+    await tester.pump();
+    await reveal(tester, find.byKey(const Key('feedback-submit')));
+    await tester.tap(find.byKey(const Key('feedback-submit')));
+    await tester.pumpAndSettle();
+    expect(sender.submissions.single.diagnosticLog, isNotNull);
+    expect(sender.submissions.single.attachments, isEmpty);
+  });
   testWidgets('uncertain delivery retains original payload for status check', (
     tester,
   ) async {
@@ -191,7 +210,7 @@ void main() {
       ),
     );
     await tester.enterText(find.byKey(const Key('feedback-message')), '旧问题');
-    await tester.ensureVisible(find.byKey(const Key('feedback-add-media')));
+    await reveal(tester, find.byKey(const Key('feedback-add-media')));
     await tester.tap(find.byKey(const Key('feedback-add-media')));
     await tester.pumpAndSettle();
     await reveal(tester, find.text('我要参与开发'), backwards: true);
@@ -303,7 +322,7 @@ void main() {
       ),
     );
     await tester.enterText(find.byKey(const Key('feedback-message')), '问题');
-    await tester.ensureVisible(find.byKey(const Key('feedback-add-media')));
+    await reveal(tester, find.byKey(const Key('feedback-add-media')));
     await tester.tap(find.byKey(const Key('feedback-add-media')));
     await tester.pumpAndSettle();
     expect(find.text('screen.png'), findsOneWidget);
@@ -312,7 +331,7 @@ void main() {
     await tester.pumpAndSettle();
     expect(sender.submissions.single.attachments, hasLength(1));
     expect(find.text('screen.png'), findsOneWidget);
-    await tester.ensureVisible(find.byTooltip('移除 screen.png'));
+    await reveal(tester, find.byTooltip('移除 screen.png'), backwards: true);
     await tester.tap(find.byTooltip('移除 screen.png'));
     await tester.pumpAndSettle();
     expect(find.text('screen.png'), findsNothing);