fix: accept Ollama reasoning field in OpenAI Chat deltas

[twhittock]

Ollama's /v1/chat/completions endpoint emits reasoning output in a reasoning field (both streaming deltas and non-streaming messages), not reasoning_content which is the DeepSeek/LM Studio convention. Effect's Schema.Struct strips unknown keys, so the reasoning content was silently discarded - producing empty responses for thinking models like glm-5.2 via Ollama Cloud.

Adds reasoning as a fallback alongside reasoning_content in the delta schema, message schema, and helper function, matching how other OpenAI-compatible clients already handle this.

Refs: ollama/ollama#16853, RightNow-AI/openfang#805

Issue for this PR

Closes#34798

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Extends "OpenAI compatible" schema shape to include Ollama's reasoning field alongside the existing reasoning_content.

How did you verify your code works?

Build & run locally, observed GLM-5.2 responses from ollama cloud are now working.

Screenshots / recordings

N/A

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

If you do not follow this template your PR will be automatically rejected.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

I found a related PR that appears to be addressing the same issue:

PR #35284: fix(llm): accept \reasoning` field in OpenAI-compatible streams`
#35284

This PR appears to be directly related to the current PR #36068 since both are working on accepting the reasoning field in OpenAI-compatible streams. The earlier PR #35284 may already address this issue, so you should verify whether:

1. PR fix(llm): accept reasoning field in OpenAI-compatible streams #35284 was merged and already includes this fix
2. PR fix: accept Ollama reasoning field in OpenAI Chat deltas #36068 is updating or extending that work further
3. These PRs are actually addressing the same problem or different aspects

Additionally, PR #34283: fix(provider): expose xhigh instead of max for GLM-5.2 on OpenAI-compatible is contextually related since it also deals with GLM-5.2 handling on OpenAI-compatible providers, which is the model mentioned in your PR description.

[github-actions]

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