feat: implement ERC-8004 reputation and fix EVM domain discovery

[Ashutosh0x]

Overview

This PR implements the ERC-8004 Trustless Agents reputation extension for the x402 protocol and fixes critical signature verification issues on EVM.

Key Changes

1. ERC-8004 Reputation Extension (@x402/extensions)

• Identity Primitives: Implemented AgentIdentity (CAIP-10) and ReputationInfo schemas using Zod.
• SATI Integration: Added FeedbackFileSchema supporting CAIP-220 Task References. This enables agents to link their reputation directly to payment transaction hashes, creating a verifiable proof-of-service.
• Automation Tool: Created feedbackTool.ts which automatically extracts payment data from an x402 settlement to generate standardized reputation signals.
• Bidirectional Support: Included client-side helpers for agents to provide their own identity in payment payloads.

2. EVM Domain Discovery (@x402/evm)

• Dynamic Discovery: Implemented Automatic EIP-712 Domain Discovery in the EVM facilitator. It now dynamically fetches token names and versions from the contract if they are missing or misconfigured.
• Robustness: This directly fixes the "invalid signature" issues seen with production tokens like USDC on Base Sepolia where on-chain domain parameters might vary.
• Smart Wallet Support: Addressed considerations for contract-based wallets (e.g., Coinbase Smart Wallet) by providing better error handling and documentation for switching to Permit2.

3. Spec & Documentation

• EVM Scheme Spec: Updated specs/schemes/exact/scheme_exact_evm.md with warnings about EIP-3009/EOA limitations and recommendations for Permit2.
• Extensions README: Added comprehensive API references for the new reputation extension.

Verification Results

• @x402/extensions: 210/210 tests passed (including new reputation/feedback tests).
• @x402/evm: 165/165 tests passed (including new domain discovery logic).
• Build: Successfully built core and extensions packages to verify type safety.
• Changeset: Added minor version changeset for both packages.

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[cb-heimdall]

🟡 Heimdall Review Status

Requirement	Status	More Info
Reviews	🟡 0/1	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 1 Sum 2

[Ashutosh0x]

Hi maintainers! I've implemented the ERC-8004 reputation extension and a dynamic EIP-712 domain discovery fix for the EVM facilitator (addressing the USDC 'USD Coin' naming mismatch on Base).

All 375+ unit tests passed locally across @x402/extensions and @x402/evm. Could you please approve the CI workflows so we can verify the builds?

(Note: I'll be adding a verified commit shortly to resolve the signature requirement). Thanks!