Add python 3.14 to supported versions (#1599)

* Add python 3.14 to our supported versions and to our CI
* Convert to use pyproject.toml standard dependency groups
* Fix any issues reported by CI

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Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

.readthedocs.yml

@@ -11,12 +11,8 @@ build:
   tools:
     python: "3"
   jobs:
+    install:
+      - pip install --upgrade pip
+      - pip install --group 'docs'
     pre_build:
       - python -m sphinx -b linkcheck docs/source/ $READTHEDOCS_OUTPUT/linkcheck
-
-python:
-  install:
-    - method: pip
-      path: .
-      extra_requirements:
-        - docs