[0xpantera]

Summary

• add a signerd-backed WalletBeat local-chain QA lane (qa:walletbeat:local-chain)
• add a QA-only signerd supervisor example that owns the private resolver capability channel and auto-approves throwaway local-chain requests
• exercise the extension + real browser bridge + real unlocked signerd path for native send, ERC-20 transfer/approve, personal_sign, SIWE-style personal_sign, EIP-712, and eth_sign refusal
• keep the lane confined to a fresh temp config dir, local Anvil chain, and ignored test artifacts

Test Plan

• cargo fmt --all --check
• just check
• cargo test --workspace
• pnpm run qa:extension
• pnpm run qa:extension:real
• pnpm run qa:walletbeat
• pnpm run qa:walletbeat:signatures
• pnpm run qa:walletbeat:transactions
• pnpm run qa:walletbeat:local-chain
• git diff --check

Closes #93