Add embeddings manifest to workflow and update docs per workflow

[prrao87]

Clarify embedding docs across SDKs and Enterprise behavior.

• Add TypeScript and Rust coverage for embedding function setup.
• Add TypeScript snippets directly into the embedding quickstart walkthrough.
• Clarify that Enterprise query-time embedding generation happens in the client via the local SDK registry, not on the server.
• Explain when string search falls back to FTS versus vector search.
• Document registry $var: usage, fallbacks, and multiple embedding-column concepts.
• Remove redundant quickstart examples now covered by the walkthrough.

[mintlify]

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Project	Status	Preview	Updated (UTC)
lancedb-bcbb4faf	🔴 Failed	–	May 6, 2026, 2:14 PM

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