ollama: send keep_alive at top level

[chinmaynadgir]

fixes #256 This PR aligns the Ollama provider with the Ollama API by sending keep_alive at the payload’s top level while keeping options.keep_alive for backward compatibility.

Changes
Provider: compute keep_alive once, set payload['keep_alive'] and options['keep_alive'].

Tests: in tests/inference_test.py:
test_ollama_extra_kwargs_passed_to_api: assert payload['keep_alive'] == 600.
test_ollama_defaults_when_unspecified: assert payload['keep_alive'] == 300.

Compatibility
Backward-compatible: options.keep_alive is still present. No breaking API changes.

[github-actions]

⚠️ Branch Update Required

Your branch is 1 commits behind main. Please update your branch to ensure CI checks run with the latest code:

git fetch origin main
git merge origin/main
git push

Note: Enable "Allow edits by maintainers" to allow automatic updates.

[github-actions]

⚠️ Branch Update Required

Your branch is 3 commits behind main. Please update your branch to ensure CI checks run with the latest code:

git fetch origin main
git merge origin/main
git push

Note: Enable "Allow edits by maintainers" to allow automatic updates.