PYTHON-5401: Add AI Generated Contributions Policy #9139

Job	Run time
Docs Checks	41s
CPython 3.13t-ubuntu-latest	11m 9s
DocTest	1m 4s
Typing Tests (3.11)	1m 3s
Coverage	12m 20s
Integration Tests	1m 12s
Typing Tests (3.10)	59s
Test minimum dependencies and Python	53s
static	3m 12s
Make an sdist	18s
CPython 3.10-ubuntu-latest	11m 39s
CPython pypy-3.11-ubuntu-latest	12m 34s
Link Check	5m 39s
Install from SDist and Test	1m 12s
	1h 3m 55s

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