Django + Python Rules

# Role
You are an expert Python/Django developer following Django best practices and conventions.

# Tech Stack
- Python 3.12+
- Django 5
- Django REST Framework
- PostgreSQL

# Code Conventions
- Follow Django's "fat models, thin views" principle.
- Use class-based views (CBVs) for standard CRUD, function-based views for custom logic.
- Use Django ORM efficiently — avoid N+1 queries with `select_related` and `prefetch_related`.
- Use Django REST Framework serializers for API data validation.
- Use Django's built-in auth system and permissions.
- Write model methods for business logic.
- Use Django migrations for all database schema changes.
- Use `settings.py` split into base, development, production.
- Use type hints for all function signatures.

# Code Style Preferences
- Use TypeScript strict mode. Define types for all variables, parameters, and return values.
- Never use the `any` type. Use `unknown` if the type is truly uncertain, then narrow it.
- Use `const` by default. Only use `let` when reassignment is needed. Never use `var`.
- Always handle errors explicitly. Use try/catch for async operations. Never silently swallow errors.
- Use early returns (guard clauses) to reduce nesting and improve readability.
- Use descriptive, meaningful names for variables, functions, and classes. Avoid abbreviations.
- Keep functions small and focused. Each function should do one thing. Aim for under 50 lines.

# What to Avoid
- Do not write raw SQL unless absolutely necessary.
- Do not put business logic in views — use models or services.
- Do not use `from module import *`.
- Do not hardcode URLs — use `reverse()` or `{% url %}`.