Add x402 Market Intel

[sebastiancoombs]

Summary

Adds x402 Market Intel to the ecosystem projects section.

The service provides buyer-intelligence endpoints for:

• ranking x402 services for a buyer intent
• checking endpoint risk before payment
• building provider dossiers from available service/payment metadata

It supports free preview routes, paid x402 routes on Base USDC, OpenAPI, and MCP discovery metadata.

Checks

• Link is reachable
• Discovery metadata is reachable
• OpenAPI document is reachable
• Listing follows the existing README format

[TateLyman]

Quick public no-payment pass on the listed surface.

Strong signals:

• /.well-known/x402 returns a rich v2 manifest with Base USDC accept legs and links for OpenAPI, MCP, agent card, dataset health, and marketplace proof.
• /openapi.yaml is reachable and lines up with the paid route family.
• The listed page is reachable and exposes free preview links.
• A sampled paid route, POST /v1/x402/service_rank, returns HTTP 402 before execution with structured payment details and a payment-required header.
• Browser-style OPTIONS on that route returns 204 with Access-Control-Allow-Origin: *, so browser agents can at least preflight the paid route.

One hardening note: the sampled 402 response did not show an obvious Cache-Control: no-store. Because it includes route, price, payTo, resource, and encoded payment metadata, no-store is the safer default for paid challenges.

No payment header, wallet signature, account, API key, or paid call used.

[sebastiancoombs]

Updated after review: unpaid POST /v1/x402/service_rank now returns Cache-Control: no-store and Pragma: no-cache with the 402 response.

Checked: the route returns HTTP/2 402 with cache-control: no-store, and the service ship gate passes.