remove duplicate panes for text/html rendering : dokieli-pane and human pane

[bourgeoa]

dokieli-pane is is displayed for rendering text/html document and human pane does exactly the same
This is a 100% duplicate in the mashlib UI.

Human pane covers all tex/html rendering : dokieli, markdown and simple .html document.

We can :

• suppress dokieli rendering which is a duplicate code
• or check for dokieli in the html content to display an icon which is html content depending : markdown, dokieli, other human rendering

both solutions have been agreed by the dokieli staff.
In any case we shall keep the dokieli app creation

[bourgeoa]

Pull Request Summary

Summary

Consolidated dokieli and HTML rendering in humanReadablePane, removed blob URL usage, and implemented dynamic async icon detection for panes.

Changes

Solid Panes - humanReadablePane.js

• ✅ Replaced blob URL creation with direct subject.uri for iframe src
• ✅ Implemented dynamic icon function returning:
  • markdown.svg for markdown files (detected by extension)
  • dokieli-logo.png for dokieli documents (detected by content)
  • Default icon for other HTML/media files
• ✅ Added async icon detection with Promise support for unfetched content
• ✅ Consolidated dokieli rendering logic (previously duplicated in dokieliPane)
• ✅ Dynamic height calculation based on content: dokieli files get -10 lines adjustment
• ✅ Added allow-forms to iframe sandbox permissions for dokieli form submission

Solid Panes - dokieliPane.js

• ✅ Removed render function (consolidated into humanReadablePane)
• ✅ Set label() to return null (no viewing, only creation)
• ⚠️ Kept mintNew and mintClass for dokieli document creation

Solid Panes - manager.js

• ✅ Added async icon function support with Promise detection
• ✅ Icon updates dynamically when Promise resolves

Technical Details

Icon Detection Hierarchy:

1. Markdown files: Synchronous detection by file extension
2. Cached results: Fast synchronous lookup from dokieliCache Map
3. Already-fetched content: Synchronous check of fetcher cache
4. Unfetched HTML: Async Promise that fetches content and detects dokieli

Sandbox Permissions: allow-scripts allow-same-origin allow-forms

Benefits

• 🔄 Eliminated code duplication between dokieliPane and humanReadablePane
• 🎯 Proper icon display for markdown and dokieli documents
• 🚀 Performance: Synchronous detection when content is cached
• 🔒 Maintained security with CSP-compliant direct URI loading