Support free-threaded Python aliases

[juliosuas]

Fixes #1931.

This adds the common free-threaded aliases 3.13t and 3.14t to the Python distribution list, resolving them to the existing CPython standalone freethreaded artifacts.

A couple of details are covered here:

• get_distribution("3.13t") keeps the requested alias as the distribution name while resolving sources from the base 3.13 distribution with variant_gil="freethreaded".
• Free-threaded standalone archives use the full archive layout, so their Python executable is under python/install/bin/python3.
• Installed distribution discovery no longer hard-filters directory names against the base distribution table, allowing installed 3.13t / 3.14t directories to be discovered from their metadata.

Tests:

PATH="$PWD/.venv/bin:$PATH" PYTHONPATH=src .venv/bin/python -m pytest tests/python/test_resolve.py tests/python/test_core.py -q -m "not requires_internet"
PATH="$PWD/.venv/bin:$PATH" PYTHONPATH=src .venv/bin/python -m pytest "tests/python/test_core.py::test_installation[3.13t]" "tests/python/test_core.py::test_installation[3.14t]" -q
PATH="$PWD/.venv/bin:$PATH" ruff check src/hatch/python/resolve.py src/hatch/python/core.py src/hatch/python/distributions.py tests/python/test_resolve.py tests/python/test_core.py
PATH="$PWD/.venv/bin:$PATH" ruff format --check src/hatch/python/resolve.py src/hatch/python/core.py src/hatch/python/distributions.py tests/python/test_resolve.py tests/python/test_core.py