feat(cohere): upgrade integration from ai to gen_ai

[shellmayr]

• Move everything in cohere from ai.* attributes to gen_ai.* attributes
• Purposely does not include the changes for v2 after alignment with @alexander-alderman-webb

Closes TET-2023

[linear-code]

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

[github-actions]

Semver Impact of This PR

🟡 Minor (new features)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

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New Features ✨

• (cohere) Upgrade integration from ai to gen_ai by shellmayr in #5597

Bug Fixes 🐛

• (celery) Propagate user-set headers by sentrivana in #5581
• (utils) Avoid double serialization of strings in safe_serialize by ericapisani in #5587

Documentation 📚

• (openai-agents) Remove inapplicable comment by alexander-alderman-webb in #5495
• Add AGENTS.md by sentrivana in #5579
• Add set_attribute example to changelog by sentrivana in #5578

Internal Changes 🔧

• (openai-agents) Expect namespace tool field for new openai versions by alexander-alderman-webb in #5599

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_{🤖 This preview updates automatically when you update the PR.}

[github-actions]

Codecov Results 📊

✅ 78 passed | Total: 78 | Pass Rate: 100% | Execution Time: 922ms

All tests are passing successfully.

❌ Patch coverage is 8.33%. Project has 13686 uncovered lines.

Files with missing lines (1)

File	Patch %	Lines
cohere.py	11.59%	⚠️ 122 Missing

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