Improve Bacalhau AEO and repair legacy documentation routes

[aronchick]

Summary

• define Bacalhau consistently as the Apache-2.0 open-source compute-over-data project
• add answer-first documentation, metadata, structured data, and LLM-readable resources
• repair 59 legacy documentation routes that currently land on 404 pages
• keep exactly one approved commercial relationship sentence on the Bacalhau homepage
• remove other Expanso promotion and partner assets from Bacalhau documentation

Entity boundary

The only public Expanso relationship text in this repository is: “Commercial support for Bacalhau is available through Expanso.”

Validation

• TypeScript typecheck passes
• spell check passes
• Docusaurus production build passes
• generated sitemap contains 107 URLs
• generated internal targets and local redirect destinations were checked successfully

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[aronchick]

Validation after the latest update:

• npm run build passed
• npm run typecheck passed
• npm run spell-check passed
• all 168 generated HTML pages crawled locally; 4,883 internal links/assets checked with zero missing targets
• /docs/robots.txt, /docs/sitemap.xml, and /docs/llms.txt are byte-identical copies of the canonical root machine files
• generated content contains exactly one Expanso reference: the homepage commercial-support sentence