feat: get chain contract versions

[alxdca]

Depends on #685. This PR is part of a stack created with Aviator. ➡️ feat: get chain contract versions #687 Add a docker command runner helper #685 main

Summary

• add a reusable getOrbitChainContractVersions SDK helper that runs Orbit Actions via Docker and parses the
  JSON response
• add a shared runDockerCommand utility plus unit tests that avoid leaking env secret values into logged
  argv/error metadata
• add a get-chain-contract-versions example that builds the local workspace package and prints contract
  version data for an Orbit chain

Why / Context

• consumers currently need to leave the SDK and invoke Orbit Actions manually to inspect deployed Nitro
  contract versions
• this change adds a TypeScript entry point for that workflow while keeping execution inside the existing
  offchainlabs/chain-actions Docker image
• the example gives users a concrete way to supply INBOX_ADDRESS, NETWORK, and PARENT_CHAIN_RPC and run the helper against a real chain

Risks / Notes

• the helper depends on Docker being installed and available on PATH
• the helper currently validates only the top-level JSON shape (versions and upgradeRecommendation)
  returned by Orbit Actions
• failures from the Docker process are surfaced through the shared runner with argv/stdout/stderr metadata

Test Plan

• Run pnpm vitest src/getOrbitChainContractVersions.unit.test.ts src/runDockerCommand.unit.test.ts
• Run pnpm build
• Run pnpm --dir examples/get-chain-contract-versions dev with Docker available and valid
  INBOX_ADDRESS / PARENT_CHAIN_RPC