fix: harden school imports and add optional feedback diagnostics

mobile/lib/main.dart

@@ -5,6 +5,8 @@ import 'package:path_provider/path_provider.dart';
 import 'package:timezone/data/latest.dart' as tzdata;
 
 import 'app/app_controller.dart';
+import 'app/app_version.dart';
+import 'services/diagnostic_log.dart';
 import 'app/hepan_app.dart';
 import 'app/tp_startup.dart';
 import 'data/file_snapshot_store.dart';
@@ -37,6 +39,7 @@ Widget buildApplication(
 );
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
+  DiagnosticLog.instance.add('app_started', fields: {'version': appVersion});
   AppController? controller;
   await launchApplication(
     bootstrap: () async {
@@ -45,8 +48,10 @@ Future<void> main() async {
       final gateway = PluginReminderGateway(
         onTap: (key) => selection.value = key,
       );
+      final directory = await getApplicationSupportDirectory();
+      unawaited(DiagnosticLog.instance.attach(directory));
       final value = AppController(
-        FileSnapshotStore(await getApplicationSupportDirectory()),
+        FileSnapshotStore(directory),
         LocalNotificationService(gateway),
         AndroidCalendarService(MethodCalendarGateway()),
         DateTime.now,