Email Confirmation and refactor for snackbar

frontend/pshared/lib/provider/email_verification.dart

@@ -0,0 +1,50 @@
+import 'package:flutter/material.dart';
+
+import 'package:pshared/provider/resource.dart';
+import 'package:pshared/service/account.dart';
+import 'package:pshared/utils/exception.dart';
+
+
+class EmailVerificationProvider extends ChangeNotifier {
+  Resource<bool> _resource = Resource(data: null, isLoading: false);
+  String? _token;
+
+  Resource<bool> get resource => _resource;
+  bool get isLoading => _resource.isLoading;
+  bool get isSuccess => _resource.data == true;
+  Exception? get error => _resource.error;
+
+  Future<void> verify(String token) async {
+    final trimmed = token.trim();
+    if (trimmed.isEmpty) {
+      _setResource(
+        Resource(
+          data: null,
+          isLoading: false,
+          error: Exception('Email verification token is empty.'),
+        ),
+      );
+      return;
+    }
+    if (_token == trimmed && _resource.isLoading) return;
+    _token = trimmed;
+    _setResource(Resource(data: null, isLoading: true));
+    try {
+      await AccountService.verifyEmail(trimmed);
+      _setResource(Resource(data: true, isLoading: false));
+    } catch (e) {
+      _setResource(
+        Resource(
+          data: null,
+          isLoading: false,
+          error: toException(e),
+        ),
+      );
+    }
+  }
+
+  void _setResource(Resource<bool> resource) {
+    _resource = resource;
+    notifyListeners();
+  }
+}