Ollama's OpenAI-compatible endpoint handles reasoning natively via the
`reasoning` field in streaming chunks. Treating Ollama as a
reasoning-tag provider incorrectly forces <think>/<final> tag
enforcement, which causes stripBlockTags() to discard all output
(since Ollama models don't emit <final> tags), resulting in
'(no output)' for every Ollama model.
This fix removes 'ollama' from the isReasoningTagProvider() check,
allowing Ollama models to work correctly through the standard
content/reasoning field separation.
74193ff754