ECDSA P-256 / SHA-256 detached signature over /.well-known/mcp/manifest.json
(raw DER at manifest.json.sig). The `npx datamancy` adapter pins the public key
and verifies this on every fetch.

Signature (DER, base64):

MEYCIQCitG5gySZhH+wN+HI7Uo9fWzVywlAkfvVulxA1R00GoAIhANZxA1ToNYDWeCC+TITTpOXDn3yvnvFTTOxnLDXoOA5p