[MNT] pin Python <3.14 due to pydantic v1 incompatibility with PEP 649

[xenonnn4w]

Change(s)

Change Type: Fixed

Change Category: Internal

Changelog Entry: Pin Python version to <3.14 and expand CI test matrix to cover Python 3.11–3.13.

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained.
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained.
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it (but consider if this should not be a code comment or in the documentation instead).
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.
• The PR title matches the changelog entry's one-line description.

Related Issues

• [Tests]: Pydantic validation errors when running tests on Python 3.14 #682
• Report on current status of testing in AIOD-rest-api #681