Add registrations as known spec field

[a6b8]

Problem

The RegistrationValidator does not recognize registrations as a valid field. It gets flagged as:

• REG-040: registrations: Unknown field not defined in ERC-8004 spec

But registrations is defined in the ERC-8004 spec as an optional array field.

Impact

• 9,072 false REG-040 warnings for registrations field alone

Spec Definition

From ERC-8004:

"registrations": [
  {
    "agentId": 22,
    "agentRegistry": "{namespace}:{chainId}:{identityRegistry}"
  }
]

Each registration object contains:

• agentId (number): ERC-721 token ID
• agentRegistry (string): Format {namespace}:{chainId}:{identityRegistry} (e.g., eip155:1:0x8004...)

Required Changes

In RegistrationValidator.mjs:

1. Add registrations to KNOWN_SPEC_FIELDS array
2. Add #validateRegistrations() method that validates:
   • Field is an array
   • Each entry has agentId (number) and agentRegistry (string)
   • agentRegistry format matches {namespace}:{chainId}:{address} pattern
3. Call #validateRegistrations() from validate()

Current KNOWN_SPEC_FIELDS:

const KNOWN_SPEC_FIELDS = [
    'type', 'name', 'description', 'image', 'services',
    'x402Support', 'active', 'supportedTrust'
]

Should be:

const KNOWN_SPEC_FIELDS = [
    'type', 'name', 'description', 'image', 'services',
    'x402Support', 'active', 'registrations', 'supportedTrust'
]

Validation Data

Validated against ~69,000 Dune-downloaded on-chain registration events.