[robingenz]

Summary

Python 3.9 reached end of life in October 2025. The ubuntu-latest runner (Ubuntu 26.04) no longer ships it, so the 3.9 test job fails.

• Require Python 3.10 or later (requires-python, classifiers, Ruff target).
• Remove 3.9 from the CI test matrix.
• Update the README and examples README.
• Add a BREAKING.md entry for 0.3.x.

The Ruff UP ignores stay for now. Enabling them rewrites ~540 annotations, so that belongs in a separate PR (marked with a TODO).

🤖 Generated with Claude Code

[Copilot]

🟢 Approval recommended

The focused compatibility change is consistent across package metadata, tooling, CI, and documentation, with no unresolved findings.

No open issues 🎉

What changed in this PR

This PR drops Python 3.9 support and consistently raises the SDK’s minimum supported version to Python 3.10.

Changes:

• Updates package metadata and Ruff’s target while retaining annotation-related lint ignores for a separate cleanup.
• Removes Python 3.9 from the CI test matrix.
• Updates installation requirements and documents the breaking change for 0.3.x.

File	Description
README.md	Updates the minimum Python requirement to 3.10.
pyproject.toml	Aligns package metadata and tooling with Python 3.10+.
examples/​README.md	Updates example prerequisites to Python 3.10+.
BREAKING.md	Documents the Python requirement change for 0.3.x.
.github/​workflows/​ci.yml	Removes Python 3.9 from the test matrix.

_{Review effort: Balanced}