Fix school browser initialization and redirect detection; improve diagnostics

mobile/lib/features/school/school_session.dart

@@ -12,6 +12,7 @@ import 'school_page_adapter.dart';
 import 'school_exam_adapter.dart';
 import 'school_login_flow.dart';
 import 'school_page_probe.dart';
+import 'school_browser.dart';
 
 enum SchoolConnectionState {
   signedOut,
@@ -22,7 +23,28 @@ enum SchoolConnectionState {
 }
 
 class SchoolSession extends ChangeNotifier {
-  SchoolSession();
+  SchoolSession({this.configureBrowser = configureSchoolBrowser});
+  final SchoolBrowserConfigurator configureBrowser;
+  Future<SchoolBrowserInfo>? _browserReady;
+  String? browserVersion;
+  Future<void> _loadRequest(Uri uri) async {
+    final controller = web, generation = _pageGeneration, serial = _openSerial;
+    try {
+      final info = await (_browserReady ??= configureBrowser(
+        controller,
+        'graduate',
+      ));
+      if (!hasOpened || generation != _pageGeneration || serial != _openSerial) {
+        return;
+      }
+      browserVersion = info.chromiumVersion;
+      await controller.loadRequest(uri);
+    } catch (_) {
+      _browserReady = null;
+      rethrow;
+    }
+  }
+
   // Creating Android WebView starts its browser engine. Do it on school access,
   // not while the student is opening an offline timetable.
   late final WebViewController web = _createWeb();
@@ -38,7 +60,7 @@ class SchoolSession extends ChangeNotifier {
           if (upgrade != null) {
             final generation = _pageGeneration;
             try {
-              await web.loadRequest(upgrade);
+              await _loadRequest(upgrade);
             } catch (_) {
               if (generation == _pageGeneration) {
                 _failure(
@@ -54,6 +76,12 @@ class SchoolSession extends ChangeNotifier {
                 uri,
                 isMainFrame: request.isMainFrame,
               )) {
+            DiagnosticLog.instance.resourceFailure(
+              'graduate',
+              request.url,
+              code: 'blocked_navigation',
+              mainFrame: request.isMainFrame,
+            );
             if (kDebugMode && request.isMainFrame) {
               debugPrint(
                 'Blocked school navigation origin: ${uri?.scheme}://${uri?.host}',
@@ -80,6 +108,13 @@ class SchoolSession extends ChangeNotifier {
         },
         onPageFinished: _loaded,
         onWebResourceError: (error) async {
+          DiagnosticLog.instance.resourceFailure(
+            'graduate',
+            error.url,
+            code: 'web_resource_error',
+            status: error.errorCode,
+            mainFrame: error.isForMainFrame,
+          );
           if (error.isForMainFrame != true || error.url == null) return;
           final generation = _pageGeneration;
           final current = await web.currentUrl();
@@ -94,6 +129,12 @@ class SchoolSession extends ChangeNotifier {
           }
         },
         onHttpError: (error) async {
+          DiagnosticLog.instance.resourceFailure(
+            'graduate',
+            error.request?.uri.toString(),
+            code: 'http_error',
+            status: error.response?.statusCode,
+          );
           final generation = _pageGeneration;
           final current = Uri.tryParse(await web.currentUrl() ?? '');
           if (hasOpened &&
@@ -231,7 +272,7 @@ class SchoolSession extends ChangeNotifier {
     notifyListeners();
     if (needsTermSelection) return;
     try {
-      await web.loadRequest(connected ? _target : authUrl);
+      await _loadRequest(connected ? _target : authUrl);
     } catch (_) {
       if (serial == _openSerial && generation == _pageGeneration) {
         _failure('学校入口无法打开，请检查校园网络后重试。', code: 'entry_load_failed');
@@ -264,7 +305,7 @@ class SchoolSession extends ChangeNotifier {
     _armTimeout();
     notifyListeners();
     try {
-      await web.loadRequest(_target);
+      await _loadRequest(_target);
     } catch (_) {
       if (serial == _openSerial && generation == _pageGeneration) {
         _failure('学校学期查询页面暂时无法打开，请重试。', code: 'query_load_failed');
@@ -499,7 +540,7 @@ class SchoolSession extends ChangeNotifier {
         _armTimeout();
         notifyListeners();
         try {
-          await web.loadRequest(next);
+          await _loadRequest(next);
         } catch (_) {
           if (generation == _pageGeneration) {
             _failure('课表查询页面暂时无法打开，请重试。', code: 'query_load_failed');