fix(ci): Use gh CLI to convert PR to draft

[stephanie-anderson]

The GraphQL convertPullRequestToDraft mutation doesn't work with GitHub App installation tokens ("Resource not accessible by integration"). This switches to gh pr ready --undo which handles the auth correctly via the GH_TOKEN env var.

Also splits the workflow into two steps: draft conversion via gh CLI, then labeling + commenting via actions/github-script.

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

📋 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 ✨

Langchain

• Set gen_ai.operation.name and gen_ai.pipeline.name on LLM spans by ericapisani in #5849
• Broaden AI provider detection beyond OpenAI and Anthropic by ericapisani in #5707
• Update LLM span operation to gen_ai.generate_text by ericapisani in #5796

Bug Fixes 🐛

Ci

• Use gh CLI to convert PR to draft by stephanie-anderson in #5874

• Use GitHub App token for draft PR enforcement by stephanie-anderson in #5871

Internal Changes 🔧

Langchain

• Add text completion test by alexander-alderman-webb in #5740
• Add tool execution test by alexander-alderman-webb in #5739
• Add basic agent test with Responses call by alexander-alderman-webb in #5726
• Replace mocks with httpx types by alexander-alderman-webb in #5724
• Consolidate span origin assertion by alexander-alderman-webb in #5723
• Consolidate available tools assertion by alexander-alderman-webb in #5721

Other

• (asyncpg) Normalize query whitespace in integration by ericapisani in #5855
• Add note to coordinate with assignee before PR submission by sentrivana in #5868
• Temporarily stop running litellm tests by alexander-alderman-webb in #5851

Other

• ci+docs: Add draft PR enforcement by stephanie-anderson in #5867

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

[github-actions]

Codecov Results 📊

✅ 54 passed | ⏭️ 2 skipped | Total: 56 | Pass Rate: 96.43% | Execution Time: 7.31s

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 13203 uncovered lines.

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Generated by Codecov Action