Add environment configuration and email settings

- Created a new .env.example file for environment variable configuration including Django settings, email configurations, and common SMTP provider examples.
- Updated .vscode/settings.json to include additional words for spell checking.
- Enhanced config/settings.py to load environment variables using python-dotenv, added data directory management, and configured email settings.
- Updated config/urls.py to include debug toolbar URLs conditionally based on testing.
- Added pytest configuration in conftest.py for Django testing.
- Created core application with custom User model, admin registration, and migrations.
- Implemented tests for User model and admin functionalities.
- Updated pyproject.toml to include new dependencies for debugging and environment management.
- Updated uv.lock to reflect new package versions and dependencies.

conftest.py

@@ -0,0 +1,24 @@
+from __future__ import annotations
+
+# Pytest configuration for Django testing
+import os
+
+import django
+from django.conf import settings
+from django.contrib.auth.models import update_last_login
+from django.contrib.auth.signals import user_logged_in
+
+
+def pytest_configure() -> None:
+    """Configure Django settings for pytest."""
+    if not settings.configured:
+        os.environ.setdefault("DJANGO_SETTINGS_MODULE", "config.settings")
+        django.setup()
+
+        # Use faster password hasher for tests
+        settings.PASSWORD_HASHERS = [
+            "django.contrib.auth.hashers.MD5PasswordHasher",
+        ]
+
+        # Disconnect update_last_login signal to avoid unnecessary DB writes
+        user_logged_in.disconnect(update_last_login)