docs: add positioning summary and harper.fast cross-reference to llms.txt

[Ethan-Arrowood]

What

Two small additions to the @signalwire/docusaurus-plugin-llms-txt config so the generated llms.txt is better framed for crawlers/agents:

1. siteDescription — adds a positioning blockquote under the # Harper Docs header. Previously the file jumped straight to ## search with no context.
2. optionalLinks — a cross-reference to harper.fast and its companion llms.txt, so an agent that lands on either file can discover the other.

Why

In an internal review of our llms.txt files, two gaps were flagged: the docs file had no top-level positioning paragraph (most well-crafted llms.txt files — Anthropic's, Cloudflare's, LangChain's — open with one), and the docs/marketing files didn't reference each other. A crawler is more likely to fetch the docs file for technical queries, so it should still carry the product framing on its own.

Before / after (top of build/llms.txt)

Before

# Harper Docs


## search

After

# Harper Docs

> Harper is a single in-process runtime that unifies your database, application logic, APIs, caching, real-time messaging, and agent loops, replicated across a multi-region data application fabric. This site is the official technical documentation: guides, API and configuration reference, and Fabric operations.


## fabric

…and in the Optional links section:

- [Harper product overview (harper.fast)](https://www.harper.fast): Marketing site with positioning and use cases; companion llms.txt at https://www.harper.fast/llms.txt

Testing

npm run build succeeds (372 documents processed) and build/llms.txt contains the blockquote and the cross-reference link as shown above.

Refs HarperFast/ospo#24, HarperFast/ospo#25

🤖 Generated with Claude Code

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