feat: add Evotor OAuth connection feature with formatted phone input

- Add EvotorConnection model to store user's Evotor access tokens
- Implement OAuth 2.0 flow: /evotor (view), /evotor/connect, /evotor/callback, /evotor/disconnect
- Add Evotor connection page with connected/disconnected states
- Implement phone input masking (+7 (XXX) XXX-XX-XX) using Inputmask
- Add Russian validation messages for form fields
- Update phone validator to match masked format
- Add httpx dependency for async OAuth token exchange
- Add Evotor settings to config: CLIENT_ID, CLIENT_SECRET, SCOPES

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

web/templates/base.html

@@ -18,6 +18,9 @@
             <div class="collapse navbar-collapse" id="navbarNav">
                 <ul class="navbar-nav ms-auto">
                     {% if user %}
+                        <li class="nav-item">
+                            <a href="/evotor" class="nav-link">Эвотор</a>
+                        </li>
                         <li class="nav-item">
                             <a href="/profile" class="nav-link"><i class="bi bi-person-circle me-1"></i>Личный кабинет</a>
                         </li>
@@ -56,5 +59,30 @@
     </main>
 
     <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/npm/inputmask@5.0.9/dist/inputmask.min.js"></script>
+    <script>
+        document.addEventListener('DOMContentLoaded', function() {
+            var phoneInputs = document.querySelectorAll('input[name="phone"]');
+            if (phoneInputs.length) {
+                Inputmask('+7 (999) 999-99-99', {
+                    placeholder: '_',
+                    showMaskOnHover: false,
+                    clearMaskOnLostFocus: false
+                }).mask(phoneInputs);
+            }
+        });
+    </script>
+    <script>
+        document.addEventListener('invalid', function(e) {
+            if (e.target.validity.valueMissing) {
+                e.target.setCustomValidity('Пожалуйста, заполните это поле');
+            } else if (e.target.validity.typeMismatch) {
+                e.target.setCustomValidity('Пожалуйста, введите корректное значение');
+            }
+        }, true);
+        document.addEventListener('input', function(e) {
+            if (e.target.required) e.target.setCustomValidity('');
+        }, true);
+    </script>
 </body>
 </html>