feat: Python bindings (PyO3) for offline receipt verification and escrow access

[mahirhir]

Summary

The core receipt verification and Merkle tile log verification engines are written in Rust (gx-core, gx-receipt, gx-tile). Adding Python bindings via pyo3 / maturin will allow Python-based agent runtimes (LangChain, CrewAI, DSPy, custom scripts) to verify DSSE receipts and query tile logs without shelling out to the gx binary.

Scope

• Crate: crates/gx-py (new)
• Wrap gx_receipt::verify_receipt(receipt_bytes, public_key)
• Wrap gx_tile::verify_inclusion_proof(entry, tile_roots)
• Publish wheel build via GitHub Actions (maturin-action)

Good first issue for anyone familiar with PyO3 / Maturin.

[mahirhir]

Status as of 2026-09-01: not started. Two corrections so nobody chases stale names: the workspace no longer has gx-receipt / gx-tile crates — receipt and log verification live in gx-witness and gx-log today. And the tracefold package on PyPI is a 0.0.1 name reservation only; it contains no bindings.

Anyone picking this up should target a new crates/gx-py wrapping the verify path in gx-witness. Still a good first issue.