fix: use Ajv 2020 for trust schemas

[GsCommand]

Motivation

• Trust schema JSON files declare $schema: "https://json-schema.org/draft/2020-12/schema", and runtime validation fails with no schema with key or ref "https://json-schema.org/draft/2020-12/schema" when using the default Ajv export.
• The change aligns the validator with the schemas' draft version without modifying the schema files or changing receipt/proof behavior.

Description

• Replace the default Ajv import with Ajv2020 from ajv/dist/2020 and instantiate it via new Ajv2020({ allErrors: true, strict: false }) in src/trust.ts.
• Update the AddFormats typing to accept Ajv2020 and preserve ajv-formats wiring by calling addFormats(ajv) as before.
• Keep the trust schema JSON files unchanged and preserve existing schema registration and compile calls (ajv.addSchema and ajv.compile).
• Only src/trust.ts was modified to perform the switch to Ajv 2020.

Testing

• Ran npm install which failed with a registry error 403 Forbidden - GET https://registry.npmjs.org/ajv, so dependency installation did not complete and prevented further automated steps from running.
• npm run build was not executed because npm install failed.
• npm test was not executed because npm install failed.

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Codex Task