chore(llm): Make cross-repo search optional and remove file cleanup

[github-actions]

Note

The pull request "chore(llm): Make cross-repo search optional and remove file cleanup" was created by @chargome but did not reference an issue. Therefore this issue was created for better visibility in external tools like Linear.

1. Removes file cleanup instructions - The report markdown file no longer needs to be deleted when running in CI, since the Docker container shuts down automatically. This eliminates unnecessary cleanup logic.

2. Makes cross-repo searches conditional - Cross-repo searches in sentry-javascript-bundler-plugins and sentry-docs are now optional and only performed when relevant to the issue:

   • Bundler plugins: Only search when the issue involves build tools, bundlers, source maps, or webpack/vite/rollup
   • Docs: Only search when clarification is needed about documented behavior

[linear]

JS-1752