feat: add Hyperliquid bridge commands

[kome12]

Summary

• Add nansen bridge top-level command for EVM ↔ Hyperliquid bridging via Relay
  • nansen bridge quote — get bridge quotes (fees, steps, execution type)
  • nansen bridge execute — sign and broadcast all steps (EVM txs or EIP-712 for HL withdrawals)
  • nansen bridge status — check bridge completion status
• Calls nansen-api /api/v1/bridge/* endpoints
• Supports local wallets and Privy server wallets
• Reuses existing signing infra (signEvmTransaction, hashTypedData, signSecp256k1)

Supported flows

• Deposit (EVM → HL): signs legacy EVM txs (approve + deposit), broadcasts via RPC, polls status
• Withdraw (HL → EVM): signs EIP-712 messages (authorize + deposit), proxies via /bridge/execute, polls status

Files changed

• src/bridge.js (new) — core bridge module
• src/trading.js — export evmRpcCall, getQuotesDir, safeQuotesPath for reuse
• src/rpc-urls.js — add arbitrum, polygon, bnb RPC endpoints
• src/cli.js — register bridge commands, update help text

Test plan

• E2E deposit: 10 USDC Base → 8.78 USDC on Hyperliquid (via dev API)
• E2E withdraw: 8.78 USDC Hyperliquid → 8.76 USDC on Base (via dev API)
• Status polling works for both directions
• Quote displays fees, steps, and execution type correctly
• Unit tests

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