feat(registry): add Arbitrum Bridge plugin (ETH/ERC20)

[WuodOdhis]

Summary

Related Issue(s): Closes #244

Adds a new Arbitrum Bridge plugin to the @emberai/onchain-actions-registry that enables ETH and ERC20 bridging between Ethereum (L1) and Arbitrum (L2). The plugin exposes:

• Actions (type bridge):
  • bridge-deposit: L1 → L2
  • bridge-withdraw: L2 → L1
• Queries:
  • getMessageStatus: Inspect cross-chain message lifecycle

Networks: Arbitrum One (42161) and Arbitrum Sepolia (421614)

Type of Change:

• ✨ New feature (adds functionality)
• 🔌 Protocol integration (adds support for new DeFi protocol)
• 🧪 Tests (adding or updating tests)
• 📚 Documentation (updates to docs)

Key files:

• typescript/onchain-actions-plugins/registry/src/plugins/arbitrum-bridge/adapter.ts
• typescript/onchain-actions-plugins/registry/src/plugins/arbitrum-bridge/index.ts
• typescript/onchain-actions-plugins/registry/src/plugins/arbitrum-bridge/README.md
• Tests under typescript/onchain-actions-plugins/registry/tests/*arbitrum-bridge*.int.test.ts
• Vitest config: typescript/onchain-actions-plugins/registry/vitest.config.ts

🧪 Testing

Tests Performed:

• Integration tests for ETH and ERC20 deposit/withdraw flows
• Message status query validation
• Optional verification via L1 Inbox logs during deposit

Test Results:

• New integration tests passing locally with live Arbitrum RPCs (Tenderly Virtual Nets recommended)

Steps to Run Tests:

• From repo root or the registry package:
  • Registry package path: typescript/onchain-actions-plugins/registry
• Set RPCs (Tenderly VNets recommended):

export ETHEREUM_MAINNET_RPC_URL="https://virtual.mainnet.eu.rpc.tenderly.co/<your-id>"
export ARBITRUM_ONE_RPC_URL="https://virtual.arbitrum.eu.rpc.tenderly.co/<your-id>"

• Run L1→L2 and ERC20 tests:

USE_LIVE_CHILD=1 BRIDGE_TEST_TIMEOUT=600000 pnpm exec vitest run \
  tests/arbitrum-bridge.int.test.ts \
  tests/arbitrum-bridge-erc20.int.test.ts

• Optional: verify deposit via L1 Inbox logs:

VERIFY_DEPOSIT=1 USE_LIVE_CHILD=1 BRIDGE_TEST_TIMEOUT=600000 pnpm exec vitest run \
  tests/arbitrum-bridge-verify.int.test.ts

• Optional: run withdraw/L1↔L3 tests if configured:

USE_LIVE_CHILD=1 BRIDGE_TEST_TIMEOUT=600000 pnpm exec vitest run \
  tests/arbitrum-bridge-withdraw.int.test.ts \
  tests/arbitrum-bridge-l1l3.int.test.ts

Checklists

Code Quality

• Code follows project conventions and style guidelines
• TypeScript compilation passes (pnpm build)
• Linting passes (pnpm lint:check)
• All tests pass (pnpm test)
• No any types introduced
• Error handling implemented appropriately
• Security best practices followed (no exposed secrets/keys)

Documentation

• Code is self-documenting or includes necessary comments
• README updated if applicable (added plugin README)
• API/interface changes documented
• Breaking changes noted in description

Agent/MCP Specific (if applicable)

• MCP protocol compliance verified
• Agent skills and tools properly defined
• Error handling for external API failures
• Rate limiting and retry logic implemented
• Configuration options documented

Deployment Notes

Deployment Considerations:

• Ships within @emberai/onchain-actions-registry; no special deployment steps

New or Changed Environment Variables:

• None required for runtime
• For tests: ETHEREUM_MAINNET_RPC_URL, ARBITRUM_ONE_RPC_URL
• Optional (tests only): USE_LIVE_CHILD, BRIDGE_TEST_TIMEOUT, VERIFY_DEPOSIT

Breaking Changes or Migration Steps:

• None

New Dependencies Added:

• @arbitrum/sdk (used by the bridge adapter to build TransactionPlans)

Additional Context

• The adapter uses EthBridger and Erc20Bridger from @arbitrum/sdk to construct transaction plans.
• Registry wiring auto-registers the plugin for 42161 and 421614.
• Known caveat: Some L2 gateway RPC calls can stall on local L2 forks; prefer a live Arbitrum RPC for tests.