Add Python 3.10-3.13 to CI test matrix

[Copilot]

Expands CI coverage from Python 3.9 only to Python 3.9-3.13 to ensure compatibility across supported versions.

Changes

• Updated .github/workflows/ci-test.yml matrix to test on Python 3.9, 3.10, 3.11, 3.12, and 3.13

matrix:
  python-version: [ '3.9', '3.10', '3.11', '3.12', '3.13' ]

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Test this repository on Github actions on multiple versions of python</issue_title>
<issue_description></issue_description>

<agent_instructions>Up to python v3.13</agent_instructions>

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

• Fixes Test this repository on Github actions on multiple versions of python #28

---

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.