[stdlib] Allow loop.create_task eager_start on Python 3.13 - #16142

Refreshed the branch with current main in 6e276e8, which brings in the upstream fixes for both unrelated failures from the original run: the Python 3.15 _ctypes.dllist stub and the stub_uploader dependency pin. After the merge, pre-commit and structure checks passed; mypy on stdlib/asyncio passed for Python 3.13 and 3.14; the stdlib regression cases passed for 3.13 and 3.14; ty passed for stdlib/asyncio on 3.13; and the Pyright regression suite passed on 3.13. The host-dependent stdlib stubtest is not part of that proof because this local macOS Python lacks Tk and several curses runtime symbols; current main CI is green and the refreshed PR CI will provide the full matrix.

The usual comments about tests apply here as well.

Thanks for the reminder. I removed the routine regression-test additions in f73f35d, leaving the PR scoped to the two stub signature gates.

Verified locally:

• pre-commit run --files stdlib/asyncio/base_events.pyi stdlib/asyncio/events.pyi stdlib/@tests/test_cases/asyncio/check_task.py — passed
• python tests/mypy_test.py stdlib/asyncio -p 3.13 — 32 files passed
• python tests/pyright_test.py stdlib/asyncio --pythonversion 3.13 -p pyrightconfig.stricter.json — 0 errors and 0 warnings
• python tests/ty_test.py stdlib/asyncio --python=.venv --python-version 3.13 — 32 stubs passed

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉