Add optional SATS-402 wrapper example for Bitcoin-native paid delivery

[Lumen-Founder]

Summary

Adds a small optional SATS-402 wrapper example/docs entry for Bitcoin-native paid delivery of Firecrawl MCP/API responses.

This is unofficial and optional. It can be moved, edited, or reduced by maintainers.

The standalone proof repo is:

https://github.com/Lumen-Founder/firecrawl-sats402-wrapper

Related issue:

#220

Notes

• Does not bypass Firecrawl auth.
• Does not bypass Firecrawl billing.
• Does not bypass Firecrawl API keys.
• Does not bypass Firecrawl rate limits or usage limits.
• Real upstream mode uses a normal FIRECRAWL_API_KEY.
• The proof path uses local real-LND regtest for the SATS-402 hold-invoice/payment/preimage settlement.

Demo command:

npm run firecrawl:demo -- --url https://tvp.fund/philosophy/