Address PR #413 R1 P2: include .readthedocs.yaml in workflow path filters

Reviewer caught that the new sphinx-build job mirrors .readthedocs.yaml
(Python version, pandoc apt package, post_install docs deps) but the
workflow's path filters omitted .readthedocs.yaml. A future PR changing
only RTD config (e.g., Python version bump or new apt package) would
skip this docs-build guard, allowing drift between CI's mirror and what
RTD actually does.

Added '.readthedocs.yaml' to both push.paths and pull_request.paths.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: igerber

.github/workflows/docs-tests.yml

@@ -13,6 +13,9 @@ on:
       # file itself.
       - 'tests/conftest.py'
       - 'pyproject.toml'
+      # sphinx-build job mirrors RTD setup; trigger when RTD config drifts
+      # (Python version, apt packages, post_install docs deps).
+      - '.readthedocs.yaml'
       - '.github/workflows/docs-tests.yml'
   pull_request:
     branches: [main]
@@ -23,6 +26,9 @@ on:
       - 'tests/test_doc_snippets.py'
       - 'tests/conftest.py'
       - 'pyproject.toml'
+      # sphinx-build job mirrors RTD setup; trigger when RTD config drifts
+      # (Python version, apt packages, post_install docs deps).
+      - '.readthedocs.yaml'
       - '.github/workflows/docs-tests.yml'
   schedule:
     # Weekly Sunday 6am UTC - smoke test that snippets still execute