Add PyPI publish workflow

[Copilot]

Adds GitHub Actions workflow to automate package publishing to PyPI when releases are created.

Changes

• .github/workflows/publish-to-pypi.yml: Workflow that triggers on release publication
  • Builds source distribution and wheel using python -m build
  • Publishes via trusted publishing (OIDC) - no API tokens required
  • Uses Python 3.10 environment with minimal permissions

Setup Required

Configure trusted publishing on PyPI:

• Owner: 5enxia
• Repository: langgraph-a2a-server
• Workflow: publish-to-pypi.yml
• Environment: pypi

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add pypi publish github actions workflow</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Add pypi publish github actions workflow #5

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.