tensordict: add build-tensordict.yml for riscv64 wheels

[luhenry]

• Package: tensordict
• Version: 0.14.0
• Source: https://github.com/pytorch/tensordict
• Docs: https://github.com/pytorch/tensordict

Compiles a small pybind11 extension (tensordict._C, key-unraveling helpers) that does not link libtorch; torch is a pure runtime dependency, already published on pypi.riseproject.dev. Upstream publishes no riscv64 wheel.

Mirrors upstream's build-wheels-linux.yml, narrowed to a plain cibuildwheel build since upstream's own pytorch/test-infra reusable workflow doesn't apply here.

Differs from upstream

• Sets SETUPTOOLS_SCM_PRETEND_VERSION - pins a clean wheel version instead of setuptools_scm's git-derived +g<sha> default.
• pip install cmake in before-build - setup.py shells out to cmake directly, not a pyproject.toml build dependency.

Matrix: cp312/cp313/cp314/cp314t only - torch has no riscv64 wheel on pypi.riseproject.dev for cp310/cp311.

Testing

• same as upstream (test/smoke_test.py)
• torch/numpy/orjson resolved from pypi.riseproject.dev; public PyPI ships no riscv64 wheel for any of the three.

License: OK

Patches

• 0001-csrc-request-only-Development.Module-from-FindPython.patch - To upstream (not submitted; this repo does not open issues/PRs on third-party repositories). CMake's Development component pulls in Development.Embed, which fails on manylinux's static-libpython builds; an extension module only needs Development.Module. Reproduces on manylinux x86_64/aarch64 too, not just riscv64.

Built on cp312; smoke test passed.