Address code review feedback: remove explicit llvmlite pin

- Remove explicit llvmlite>=0.44.0 pin as numba>=0.61.0 automatically pulls compatible version
- Add changelog entry for Python 3.11+ dependency fix

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

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

pyproject.toml

@@ -36,7 +36,6 @@ dependencies = [
     "openai~=1.74.0",
     # Explicit dependency pins for Python 3.11+ compatibility
     "numba>=0.61.0",
-    "llvmlite>=0.44.0",
 ]
 
 [project.urls]