🐛 Use buttons for Termynal controls

[tiangolo]

Summary

• render the Termynal fast and restart controls as semantic buttons
• preserve their terminal styling and add explicit hover feedback
• remove link-only behavior that caused external-link presentation in the docs

This mirrors fastapi/typer#1912. The controls perform actions rather than navigation, so buttons avoid browser and documentation-theme link handling while retaining the existing behavior.

Checks

• git diff --check
• verified the focused diff matches the merged Typer implementation

AI Disclaimer

Using Codex with gpt-5.6-sol. Reviewed manually.

[github-actions]

📝 Docs preview

Last commit d0958b3 at: https://3a10f820.sqlmodel.pages.dev

Modified Pages

• https://3a10f820.sqlmodel.pages.dev/css/termynal.css - (before)
• https://3a10f820.sqlmodel.pages.dev/js/termynal.js - (before)