Bundle and slim Unix Python runtime

[seasonyuu]

Summary

• Bundle the Python runtime for Unix release artifacts so decode-runtime can load without depending on host Python installs.
• Keep the macOS Python payload relocatable while reducing it from a full multi-version Python.framework to a minimal current-version framework plus one stdlib copy.
• Add packaging validation that checks bundled Python dependencies, Unix/macOS runtime paths, and smoke-tests the packaged CLI.

Changes

• Linux/macOS CI now uses actions/setup-python with Python 3.13 for packaging consistency.
• Unix bundles include Python runtime files; dsview-core discovers bundled python/ as PYTHONHOME on non-Windows targets.
• Native runtime RPATH/RUNPATH now points at bundled Python locations.
• macOS packaging now:
  • copies only the active Python.framework/Versions/3.13/Python and required support dylibs,
  • avoids duplicating framework stdlib and standalone stdlib,
  • strips unnecessary stdlib payloads such as test, ensurepip, idlelib, tkinter, and turtledemo,
  • rewrites /Library/Frameworks/Python.framework/... dependencies to @loader_path/...,
  • ad-hoc signs modified Mach-O files so arm64 dlopen validation succeeds.
• Bundle validation now fails if macOS artifacts regress to multi-version/full-framework packaging or retain non-relocatable Python framework links.

Verification

• CI passed for the full matrix: https://github.com/LISTENAI/dsview-cli/actions/runs/24983112856
• Local Linux package validation passed:
  • python3 -m py_compile tools/package-bundle.py tools/validate-bundle.py
  • tools/package-bundle.py produced target/dsview-cli-test-x86_64-unknown-linux-gnu.tar.gz
  • tools/validate-bundle.py reported Bundle validation passed
  • smoke checks passed for dsview-cli --help, devices list --help, and decode list --format json
• Size check from the latest CI artifact:
  • dsview-cli-954859b-x86_64-apple-darwin.tar.gz: ~18 MB
  • extracted bundle: ~58 MB
  • python/: ~52 MB
  • Python.framework: ~24 MB

Notes

The previous macOS artifact from 264c79f was about 195 MB compressed and 821 MB extracted because it included four Python framework versions plus duplicate stdlib contents.