chore: declare Python 3.13/3.14 support, add 3.14 to CI (#228)

Adds Python 3.14 to the CI test matrix and lists the 3.13 and 3.14 trove
classifiers in `pyproject.toml`. `requires-python` is already `>=3.10`,
so no floor or ceiling change is needed. 3.13 was already tested in CI
but missing from the classifiers.

Verified locally on Python 3.14.7 in a fresh environment: `pytest` gives
347 passed, 3 skipped, 0 failed. The new CI matrix entry will confirm
this on Linux, macOS and Windows.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

Author: petercorke

.github/workflows/master.yml

@@ -19,7 +19,7 @@ jobs:
       matrix:
         os: [windows-latest, ubuntu-22.04, macos-latest]
         # https://devguide.python.org/versions/
-        python-version: ["3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
         exclude:
           - os: windows-latest
             python-version: "3.11"

pyproject.toml

@@ -15,6 +15,8 @@ classifiers = [
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
 
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",