biopython: add build-biopython.yml for riscv64 wheels

[luhenry]

Adds .github/workflows/build-biopython.yml, building riscv64 wheels for biopython 1.88.

Shape

Build-from-checkout with cibuildwheel, per-interpreter matrix cp312/cp313/cp314/cp314t. biopython publishes real per-interpreter cpXY-cpXY manylinux wheels (no abi3 tag anywhere in its PyPI file list), and its 13 C extension modules are declared as [[tool.setuptools.ext-modules]] in pyproject.toml with no build-time dependency beyond setuptools>=74.1 — so the build is a plain pip wheel with no before-build, no Cython, and no native deps. numpy is a runtime dependency only.

Upstream's own ci.yml has no cibuildwheel config (its build_wheels job is just python -m build --wheel per interpreter on each OS), so the workflow follows this repo's standard cibuildwheel shape and mirrors upstream's steps rather than copying a wheels.yml that does not exist.

Version vs tag

Upstream tags releases as biopython-188 for version 1.88, so the version: input stays the plain PyPI version — which is what check_versions.py compares against — and the checkout ref is derived from it in a one-line step.

Testing

Mirrors upstream's test_macos/test_windows jobs: install only numpy (plus setuptools, which run_tests.py imports for find_packages) and run cd Tests && python run_tests.py --offline. PIP_EXTRA_INDEX_URL points at our registry so numpy resolves to the riscv64 wheel we ship (2.5.2, matching PyPI's latest).

CIBW_TEST_SOURCES: Tests Bio BioSQL Doc is load-bearing and was settled by dry-running the test phase against upstream's released PyPI wheel on this host before touching CI. run_tests.py enumerates its doctest modules by walking Tests/.. with setuptools.find_packages, and several tests open data through ../Bio/Align/substitution_matrices/data/BLOSUM62, ../Doc/examples/nmr/noed.xpk and ../Doc/Tutorial/index.rst. Measured: staging Tests alone collects 209 tests and fails test_align_substitution_matrices; adding Bio BioSQL collects 501 and fails the Bio.NMR.xpktools doctest; adding Doc passes all 501, with test_Tutorial running instead of skipping.

The staged source tree cannot shadow the wheel because every command runs from Tests/, which is what lands on sys.path[0] — verified by printing Bio.__file__ from there (it resolves into site-packages). This is exactly upstream's own layout, where Bio/ sits at Tests/.. as unbuilt source while the tests import the installed build.

Two independent proofs the wheel really is compiled: the test command imports all 13 extension modules by name before running the suite, and a post-build step asserts the wheel contains exactly 13 .so files.

Licensing

The wheel ships LICENSE.rst in dist-info/licenses/ (declared via license-files in pyproject.toml), which carries both the Biopython License Agreement and the BSD 3-Clause text that the individual C file headers refer to. No external C library is vendored — every .c source is Biopython's own tree.

Local validation

YAML parses; actionlint clean apart from the expected label "ubuntu-24.04-riscv" is unknown. python -m build --wheel from the biopython-188 checkout produces a wheel with all 13 extensions on this host.