LangChain Docs & Dashboard UX

This release improves the developer experience with new documentation and dashboard enhancements. The docs now include guides for LangChain, helping users integrate Daytona's sandboxing runtime with LLM agent workflows.

To improve usability, the dashboard now displays a message if the application is loading slowly, providing better feedback. This version also includes API stability fixes. The API will now correctly reuse an existing backup registry instead of creating a new one, and a patch ensures that URL protocols are properly stripped for the legacy runner adapter.