feat: Add email settings management and templates functionality

- Implemented email settings configuration in the admin panel, allowing for SMTP settings and notification preferences.
- Created a new template for email settings with fields for SMTP host, port, username, password, sender address, and recipients.
- Added JavaScript functionality to handle loading, saving, and validating email settings.
- Introduced email templates management, enabling the listing, editing, and saving of email templates.
- Updated navigation to include links to email settings and templates.
- Added tests for email settings and templates to ensure proper functionality and validation.

tests/conftest.py

@@ -28,3 +28,35 @@ def setup_tmp_db(tmp_path, monkeypatch):
     monkeypatch.setattr("server.settings.ADMIN_PASSWORD", "admin")
     init_db()
     yield
+
+
+@pytest.fixture(autouse=True, scope="function")
+def stub_smtp(monkeypatch):
+    """Replace smtplib SMTP clients with fast stubs to avoid real network calls."""
+
+    class _DummySMTP:
+        def __init__(self, *args, **kwargs):
+            self.args = args
+            self.kwargs = kwargs
+
+        def __enter__(self):
+            return self
+
+        def __exit__(self, exc_type, exc, tb):
+            return False
+
+        def starttls(self):
+            return None
+
+        def login(self, *args, **kwargs):
+            return None
+
+        def send_message(self, *args, **kwargs):
+            return {}
+
+        def sendmail(self, *args, **kwargs):
+            return {}
+
+    monkeypatch.setattr("smtplib.SMTP", _DummySMTP)
+    monkeypatch.setattr("smtplib.SMTP_SSL", _DummySMTP)
+    yield