fix: pass github_token explicitly to claude-code-action

[yanas]

Summary

• Adds github_token: ${{ secrets.GITHUB_TOKEN }} to the Classify PR step
• Without it, claude-code-action@beta attempts to exchange the OIDC token for a Claude Code GitHub App token, which fails with 401 when the app is not installed

Test plan

• Merge and verify the next PR triggers a successful classification comment

🤖 Generated with Claude Code

[github-actions]

Claude finished @yanas's task —— View job

---

{
  "type": "fix",
  "platforms": [],
  "summary": "Adds explicit github_token to claude-code-action step in PR classification workflow to prevent 401 authentication failures when the Claude Code GitHub App is not installed."
}

[github-actions]

Warning

PR classification could not determine the PR type. Please apply a type: label manually.