test: await ky post and add delete route test

[saitejabandaru-in]

Summary

• Awaits the ky.post creation request in create.test.ts to prevent race conditions and asserts { ok: true }.
• Adds tests/routes/things/delete.test.ts to cover the delete route with URL-encoded form data and verify deletion using ky.

/claim #2

[saitejabandaru-in]

I have added the missing regression tests for request body handling and persisted responses to tighten the ky migration coverage, as pointed out in the recent issue comments. The test suite passes locally with bun test. Let me know if there is anything else needed!

[saitejabandaru-in]

Hi @tscircuit maintainers! Friendly nudge on this PR. It is mergeable, all tests pass, and it covers the request body handling/persisted responses for the ky migration as requested in issue #2. Let me know if any changes are needed!