feat: add configurable polling interval and max attempts to buildAndSubmit

[MarcusDavidG]

Summary

buildAndSubmit currently polls every 1500ms for up to 20 attempts (30s). This should be configurable per-client.

Proposed config fields

interface SharpyClientConfig {
  pollIntervalMs?: number   // default: 1500
  pollMaxAttempts?: number  // default: 20
}

Acceptance criteria

• Config fields added with documented defaults
• buildAndSubmit uses config values
• Backwards compatible — defaults match current behaviour