feat(extra): better OTEL instrumentation

[simonvdk-mistral]

Objective

• Follow more closely GenAI convention
• Remove custom MistralAI attributes, where relevant

Summary of main changes

• Don't add any GenAI attributes when it's not a GenAI operation (for instance on get agent), as per convention
• Removal of MistralAI attributes that are redundant with the GenAI or error OTEL convention
• Change span names to be as close as possible with the convention
• Add inputs, outputs, tool call arguments and results to the span attributes, following the JSONSchemas from the convention

Changes mainly impact GenAI and custom MistralAI span attributes, which are to be assumed unstable as the associated OTEL convention is not stable.

How to test

The OTEL tests are meant to serve as a basis on the main use cases we may encounter. To run them locally:

uv run python -m unittest discover -s src/mistralai_private/extra/tests -t src

Note: dependencies changes echo #406

[louis-sanna-dev]

Heads up: this still uses request._content and response._content in a few places — httpx 0.28.1 removed _content from Request objects (see #402 / #347). Should switch to the public .content property to avoid breakage.

[simonvdk-mistral]

Heads up: this still uses request._content and response._content in a few places — httpx 0.28.1 removed _content from Request objects (see #402 / #347). Should switch to the public .content property to avoid breakage.

Good catch; fixed