fix(save_html): address a critical issue where LLM secret keys are stored

[jooyoungseo]

Bug Report

Description

I have found this critical issue when working with Quarto document. Saving the LLM API keys within the iframe can cause a critical security breach in the case where users share the rendered HTML document with others.

We need to find a more secure way to store the LLM API keys.

Steps to Reproduce

Rendre the quarto document in example/quarto/demo.qmd

Actual Behavior

API keys are stored in the rendered HTML document.

Expected Behavior

API keys should not be stored in the rendered HTML document.

Screenshots

N/A

Environment

Universal

Additional Information

N/A