Add support for Message.Reasoning interactions across clients

[devcrocod]

KG-432
KG-297

Motivation and Context

A new message type has been added: Reasoning

Breaking Changes

Yes,
The implementation of Anthropic messages has been modified for future support and schema compliance

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Type of the changes

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Tests improvement
• Refactoring

Checklist

• The pull request has a description of the proposed change
• I read the Contributing Guidelines before opening the pull request
• The pull request uses develop as the base branch
• Tests for the changes have been added
• All new and existing tests passed

Additional steps for pull requests adding a new feature

• An issue describing the proposed change exists
• The pull request includes a link to the issue
• The change was discussed and approved in the issue
• Docs have been added / updated

[Copilot]

Pull Request Overview

This pull request introduces support for Message.Reasoning interactions across multiple LLM clients to implement a new reasoning capability. The feature enables AI models to expose their internal thinking processes as structured messages.

• Adds a new Message.Reasoning message type with associated Thinking interface
• Updates all client implementations to handle reasoning messages appropriately
• Modifies serialization classes to use sealed interfaces with proper role discrimination

Reviewed Changes

Copilot reviewed 21 out of 21 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
Message.kt	Adds new Reasoning message type and Thinking interface
StreamFrameExt.kt	Extends stream frame handling to support reasoning content
OpenAI clients	Implements reasoning support with proper conversion between internal types
Google client	Adds reasoning handling for thought-enabled parts
Anthropic clients	Updates message structure to sealed interfaces and adds reasoning support
Bedrock clients	Implements reasoning for Anthropic models, throws NotImplementedError for others
Ollama client	Throws NotImplementedError for reasoning (not supported)
OpenTelemetry features	Updates event handling to include reasoning messages
Memory features	Adds reasoning message formatting in conversation history

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[github-actions]

Qodana for JVM

17424 new problems were found

Inspection name	Severity	Problems
Unused import directive	🔶 Warning	16213
Check Kotlin and Java source code coverage	🔶 Warning	1198
Missing KDoc for public API declaration	🔶 Warning	11
If-Null return/break/... foldable to '?:'	◽️ Notice	2

@@ Code coverage @@
+ 70% total lines covered
15921 lines analyzed, 11209 lines covered
# Calculated according to the filters of your coverage tool

☁️ View the detailed Qodana report

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[sdubov]

Looks good for me. Open Telemetry does not have any special handling for such cases. The rest looks good from my side as well.

[EugeneTheDev]

Looks good now, thank you. A couple of small comments

[EugeneTheDev]

Let's limit it to the List<ContentPart.Text> since only text content is supported here