fix: repair Ajv ESM imports in agent-sdk

[GsCommand]

Motivation

• Fix a TypeScript build failure in src/trust.ts caused by incorrect Ajv/ajv-formats import interop so schema validation compiles under ESM/TS environments.

Description

• Update src/trust.ts imports to use ESM/TypeScript-compatible forms: changed import Ajv, { type ErrorObject } from "ajv"; to import { Ajv, type ErrorObject } from "ajv"; and changed import addFormats from "ajv-formats"; to import { default as addFormats } from "ajv-formats"; with no changes to schemas or trust receipt/proof behavior.

Testing

• Ran npm install which failed in this environment with 403 Forbidden - GET https://registry.npmjs.org/ajv so dependencies could not be fetched.
• Ran npm run build which failed because dependencies and Node type declarations were unresolved (missing ajv, ajv-formats, @types/node, and side-effect types like dotenv/config).
• Ran npm test which failed because the pretest build step failed for the same dependency/type-resolution reasons.

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Codex Task