chore: add Python 3.15 to CI test matrix and classifiers (#2850)

test: add Python 3.15 to CI test matrix and classifiers

Update the Max Python CI job from 3.14 to 3.15 and add the
Programming Language :: Python :: 3.15 classifier to pyproject.toml.

Assisted-by: OpenCode:GLM-5

.github/workflows/test.yml

@@ -85,7 +85,7 @@ jobs:
           python_version: '3.11'
         # Max Python
         - os: ubuntu-latest
-          python_version: '3.14'
+          python_version: '3.15'
         - os: ubuntu-latest
           python_version: '3.14'
           test_select: android

pyproject.toml

@@ -32,6 +32,7 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: 3.15",
     "Programming Language :: Python :: Implementation :: CPython",
     "Topic :: Software Development :: Build Tools",
 ]