chore: add tests for no item repeat binding

[radium-v]

Pull Request

📖 Description

Adds test coverage for a hydrating repeat directive (f-repeat) that has no items in its initial state. This addresses a hydration scenario where empty repeats need proper hydration markers to bind correctly during client-side activation.

🎫 Issues

• Closes fix(fast-html): a hydrating repeat with no items has no hydration markers #7211

📑 Test Plan

Added a new test case repeat directive with no item binding should not error that:

• Verifies an empty repeat renders with no list items
• Confirms hydrated comment nodes are present in the shadow DOM after hydration
• Tests that items can be dynamically added after hydration

✅ Checklist

General

• I have included a change request file using $ npm run change
• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

⏭ Next Steps

While the hydration markers documentation in RENDERING.md mentions this quirk, the document should describe this and other scenarios more clearly.