fasttext-predict: add build-fasttext-predict.yml for riscv64 wheels

[luhenry]

• Package: fasttext-predict
• Version: 0.9.2.4
• Source: https://github.com/dalf/fasttext-predict
• Docs: https://github.com/dalf/fasttext-predict

Builds the pybind11/C++ extension of fasttext-predict, a predict-only fork of Facebook's fastText with the training API stripped out. Upstream publishes no riscv64 wheel.

Mirrors upstream's wheels.yml.

Differs from upstream

• Pins the release commit instead of a tag - upstream cuts PyPI releases without ever pushing a git tag, so the commit that produced 0.9.2.4 on PyPI is pinned directly and verified byte-identical against the released sdist.
• PyPI's listed source URL (searxng/fasttext-predict) is stale; that repo/org no longer exists, the project lives at dalf/fasttext-predict now.

Testing

• Upstream ships no test suite; the wheel is exercised against the README's own language-identification example (download lid.176.ftz, predict on a French sentence, assert the extension actually compiled).

License: OK

Built on cp312; predict smoke test passed.