docs: remove stale docs/llms.txt and gitignore generated llms artifacts

[AbdelrahmanHafez]

Since 3c5d395 the llms.txt generator writes to the top level instead of docs/llms.txt, but the old docs/llms.txt was committed and never removed, so master now carries a stale copy the script will never update again.

Also, running npm run docs:generate leaves the new top-level llms.txt and ~100 docs/api/*.md files (markdown versions of the API pages for llms.txt and the copy-markdown button) as untracked clutter. Their .html siblings are already gitignored, the .md flow just never got the same treatment.

This PR:

• removes the stale docs/llms.txt
• gitignores docs/api/*.md and /llms.txt
• fixes an outdated JSDoc comment in generateLLMsTXT.js that still mentioned the old path

gh-pages keeps these ignore rules commented out so the generated files stay trackable there, #16328 adds the two new patterns to that commented block. When merging master into gh-pages, keep gh-pages's commented versions if .gitignore conflicts.

[Copilot]

Pull request overview

Removes a stale, no-longer-generated docs/llms.txt file and updates ignore rules so running docs generation doesn’t leave new LLM-related artifacts and generated API markdown as untracked clutter. This aligns the repo with the current llms.txt generation location (repo root) and keeps generated outputs out of source control on master.

Changes:

• Delete stale docs/llms.txt that is no longer updated by the generator.
• Add .gitignore entries for generated docs/api/*.md and top-level /llms.txt.
• Update scripts/generateLLMsTXT.js JSDoc to reference the correct output file location.

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated no comments.

File	Description
scripts/generateLLMsTXT.js	Fixes the JSDoc to reflect that llms.txt is generated at the repo root.
docs/llms.txt	Removes an obsolete, stale committed artifact that won’t be regenerated.
.gitignore	Ignores generated API markdown and root llms.txt to prevent untracked build artifacts.

[vkarpov15]

Thanks 👍