Implementing a Formal Experimental API Framework for Django Core

This project introduces a formal Experimental API Framework for Django by modernizing DEP 2. It implements a three-tier opt-in architecture utilizing virtual namespaces (django.experimental), centralized feature flags, and decorator engines. By establishing strict governance lifecycles and build-time safety mechanisms like an "LTS Kill-Switch", this project allows the core team to safely test, iterate, and graduate new features based on real-world feedback without compromising Django's strict backward compatibility guarantees.