v0.4.0 — Circle Wallet Integration + arc doctor

v0.4.0 — 2026-07-05

🔌 Payment Intent Demo — Circle Wallet

• Real USDC balance, tx history, gas estimates via Circle CLI
• GET /api/wallet, /api/transactions, /api/estimate
• POST /api/approve with estimate-only mode (REAL_TRANSFER=1 for real sends)

🩺 arc-builder doctor — Circle checks

• --include-circle-wallet flag (opt-in)
• Checks: CLI installed ✓ session ✓ wallet ✓ balance ✓

⚡ x402 — RpcVerifier

• On-chain tx verification via eth_getTransactionReceipt
• --verifier-mode rpc flag

🤖 CI/CD

• Matrix test (3.10-3.12), script tests, ruff lint
• CHANGELOG.md