feat(cohere): upgrade integration from ai to gen_ai

[shellmayr]

This PR encompasses multiple changes to accomplish this

• Add support for the "new" v2 of cohere which was released at the end of 2024. The cohere package continues to contain the v1 and v2 APIs, therefore we still need to support both. The instrumentation is in a separate file to prevent confusion between the versions.
• Move the auto-instrumentation for v1 from ai.* attributes to gen_ai.* attributes
• Adapt / add tests for v1 and v2
• Has been run against two new templates for cohere in the testing framework
• Semantically, Cohere is a model-provider on the level of e.g. anthropic and openai, meaning that there is no agentic flavor to this, it is "just" an API for LLM-calling for Cohere's own models

Closes TET-2023

[github-actions]

Semver Impact of This PR

🟡 Minor (new features)

📋 Changelog Preview

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New Features ✨

• (cohere) Upgrade integration from ai to gen_ai by shellmayr in #5532

Bug Fixes 🐛

• (celery) Propagate user-set headers by sentrivana in #5581

Documentation 📚

• Add AGENTS.md by sentrivana in #5579
• Add set_attribute example to changelog by sentrivana in #5578

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[github-actions]

Codecov Results 📊

✅ 13 passed | Total: 13 | Pass Rate: 100% | Execution Time: 9.92s

All tests are passing successfully.

❌ Patch coverage is 6.47%. Project has 13973 uncovered lines.

Files with missing lines (6)

File	Patch %	Lines
utils.py	16.08%	⚠️ 214 Missing
v2.py	0.00%	⚠️ 108 Missing
v1.py	0.00%	⚠️ 90 Missing
__init__.py	25.00%	⚠️ 42 Missing
span_config.py	17.65%	⚠️ 28 Missing
utils.py	0.00%	⚠️ 21 Missing

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Generated by Codecov Action

[linear]

TET-2023 Move Cohere from ai.* to gen_ai.*

[shellmayr]

This is needed because cohere sometimes uses the role chatbot in their message structure