Add custom node markdown documentation feature

[benceruleanlu]

Added documentation for a new feature that allows custom node authors to include rich markdown documentation in their WEB_DIRECTORY/docs folder. The documentation will be displayed in the UI instead of generic node descriptions, supporting localization and multimedia content.

Could the Chinese translation be reviewed? It was generated.

Related Frontend PR: Comfy-Org/ComfyUI_frontend#3922
Related Core PR: Comfy-Org/ComfyUI#8179

[comfyui-wiki]

I'm wondering whether we need an additional default document. Could we designate the sole Markdown file in the folder as the default document? Alternatively, we might prioritize en.md as the default, since the current default document seems to overlap with en.md.

I suggest implementing restrictions and requiring node authors to use the standardized localized version. In this manner, the community can assist in completing other language.

[benceruleanlu]

Could we designate the sole Markdown file in the folder as the default document?

Of course

I suggest implementing restrictions and requiring node authors to use the standardized localized version. In this manner, the community can assist in completing other language.

I don't see any way to implement this other than to remove NodeName.md, which would be limiting options for extension authors.

If they need localization functionality, they can just implement the standard NodeName/locale.md. NodeName.md is only meant as a fallback if we can't find anything localized.

[benceruleanlu]

@comfyui-wiki deployment failed without a specific error message, the next deployment succeeded, and I can access help page in local, main and feature branch, but not in prod.

Can you PTAL?

Resolved in #148