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.

core/apps.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from django.apps import AppConfig
+
+
+class CoreConfig(AppConfig):
+    """Configuration class for the 'core' Django application.
+
+    Attributes:
+        default_auto_field (str): Specifies the type of auto-created primary key field to use for models in this app.
+        name (str): The full Python path to the application.
+        verbose_name (str): A human-readable name for the application.
+    """
+
+    default_auto_field: str = "django.db.models.BigAutoField"
+    name = "core"
+    verbose_name: str = "Core Application"