feat: Add workflow helpers and wait options to TypeScript SDK

[Adarsh9977]

Summary

• Add high-level workflow helpers to @amika/sdk: createSandboxAndWait, withSandbox, and runAgent, available as AmikaClient methods and standalone exports.
• Add optional WaitOptions (timeoutMs, pollIntervalMs, signal, onPoll) to waitForSandbox, waitForSandboxStart, and waitForSandboxStop.
• Extract shared polling logic into src/wait.ts and workflow composition into src/workflows.ts.
• Add unit tests for the new helpers and wait behavior; update functional test helpers to use createSandboxAndWait.
• Document the new workflow helpers and wait options in sdk/typescript/README.md.

Test plan

• cd sdk/typescript && pnpm test
• cd sdk/typescript && pnpm typecheck
• cd sdk/typescript && pnpm build

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[Adarsh9977]

Hey @jdc123, could you please review. Once you get a chance

[jdc123]

Hey @Adarsh9977 thank you for your contribution. We're a bit swamped at the moment, but we'll review this when we have a chance.