ci: publish Linux aarch64 PyPI wheel

[TomCC7]

Summary

• build Linux aarch64 wheels on GitHub's native ARM64 runner
• validate wheel architecture, installation, exports, and Python tests before release
• merge the ARM64 artifact into the existing trusted PyPI publishing job
• document the expanded release artifact set

Validation

• parsed all modified workflow files as YAML
• ran git diff --check
• local wheel build skipped because maturin is unavailable; the new native ARM64 CI job performs the build and test