python 3.14 compatibility

Regenerated Cython C/C++ files with Cython 3.1.4 for Python 3.14 compatibility.
Fixed _PyLong_AsByteArray API changes and invalid escape sequences.
Added Python 3.13 and 3.14 to CI test matrix.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: stevenweaver

.github/workflows/python-package.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.10","3.11","3.12"]
+        python-version: ["3.10","3.11","3.12","3.13","3.14"]
 
     steps:
     - uses: actions/checkout@v3