Django REST Framework integration — `contrib/drf.py`

[dvoraj75]

Description

Create first-class DRF integration in contrib/drf.py:

• RLSTenantPermission — DRF permission class
• RLSTenantViewSetMixin — auto-sets tenant context on viewsets
• TenantContextAuthentication — authentication class that sets tenant context
• Auto-hidden tenant FK serializer field

Installable as pip install django-rls-tenants[drf].

Why

DRF is the dominant API framework for Django. Library-level integration removes boilerplate and prevents misconfiguration.

Roadmap reference

v1.5.0 — DRF Integration & Query Improvements