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.

.vscode/settings.json

@@ -1,8 +1,22 @@
 {
     "cSpell.words": [
+        "adminpass",
+        "apikey",
+        "appauthor",
+        "appname",
         "ASGI",
+        "docstrings",
+        "dotenv",
+        "Hellsén",
         "isort",
+        "Joakim",
+        "lovinator",
+        "Mailgun",
         "pydocstyle",
-        "ttvdrops"
+        "regularuser",
+        "sendgrid",
+        "testpass",
+        "ttvdrops",
+        "wrongpassword"
     ]
 }