Add freethreaded Python verification and update docs

- Added verification step to confirm freethreaded mode is active
- Updated AGENT.md to document 3.14t support
- Verification shows Python version and GIL status for 't' versions

Author: vinitkumar

.github/workflows/pythonpackage.yml

@@ -45,6 +45,12 @@ jobs:
         python-version: ${{ matrix.python-version }}
         allow-prereleases: true
 
+    - name: Verify freethreaded Python
+      if: endsWith(matrix.python-version, 't')
+      run: |
+        python --version --version
+        python -c "import sys; print('Free-threading enabled:', not sys._is_gil_enabled() if hasattr(sys, '_is_gil_enabled') else False)"
+
     - name: Install uv
       uses: astral-sh/setup-uv@v6
       with:

AGENT.md

@@ -18,5 +18,5 @@
 - Use pytest (no unittest), all tests in `./tests/` with typing annotations
 - Import typing fixtures when TYPE_CHECKING: `CaptureFixture`, `FixtureRequest`, `LogCaptureFixture`, `MonkeyPatch`, `MockerFixture`
 - Ruff formatting: line length 119, ignores E501, F403, E701, F401
-- Python 3.10+ required, supports up to 3.14
+- Python 3.10+ required, supports up to 3.14 (including 3.14t freethreaded)
 - Dependencies: defusedxml, urllib3, xmltodict, pytest, pytest-cov

plan.md

@@ -0,0 +1,8 @@
+Here is the current task
+
+
+I want to run test the latest python 3.14.0 freethreaded version
+Check the  versions-manifest.json and see where the free threaded version of python 3.14.0 is available.
+Make changes to the testing matrix, so that the supported OS and architecture for the freethreaded python in installed and these new tests for this os and arch, along with all old tests work
+
+Please introduce minimal changes to get this done and be clear and concise