Migrate tests to vitest and configure miniflare integration

[AaronDDM]

This PR migrates the test suite from Jest to Vitest and integrates Cloudflare Workers (Miniflare) testing into the CI pipeline.

Key Changes:

• Replaced Jest with Vitest: All Jest dependencies and configurations have been removed, and Vitest is now the primary test runner.
• Dual Test Environments: Configured Vitest to run tests in two environments:
  • Standard Node.js (for existing SDK tests).
  • Cloudflare Workers (using Miniflare via @cloudflare/vitest-pool-workers) to ensure compatibility with Workers environments.
• GitHub Actions Update: The pull-request.yml workflow now runs tests for both Node.js and Cloudflare Workers, ensuring comprehensive coverage across target platforms.
• Test File Conversion: All existing test files have been converted from Jest syntax to Vitest's equivalent APIs.

This change modernizes the testing infrastructure and expands test coverage to critical Cloudflare Workers environments.

License

I confirm that this contribution is made under the terms of the MIT license and that I have the authority necessary to make this contribution on behalf of its copyright owner.

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