Add markdown display support for long text fields

[emilienbidet]

Summary

This PR adds markdown display and editing capabilities to long text fields. Users can now configure long text fields to display content as markdown with a dedicated WYSIWYG editor for rich text editing.

Key Changes

Core Schema & Types

• Added LongTextDisplayType enum with Markdown option to @teable/core
• Created longTextShowAsSchema to support markdown display configuration
• Extended ILongTextFieldOptions to include optional showAs property
• Updated union schema to include long text show-as options

UI Components

• LongTextShowAs: New field setting component allowing users to toggle between plain text and markdown display modes
• MarkdownWYSIWYGEditor: Full-featured markdown editor with:
  • Text formatting toolbar (bold, italic, strikethrough, code)
  • Heading levels (H1-H3)
  • List types (bullet, numbered, task lists)
  • Block elements (quotes, code blocks, horizontal rules)
  • Link and image insertion with image upload support
  • Live preview toggle
  • Keyboard shortcuts (Ctrl+S to save, Esc to cancel)
  • Drag-and-drop and paste image support
• MarkdownExpandModal: Modal dialog for expanded markdown editing with fullscreen support
• LongTextEditor: Updated to detect markdown mode and render appropriate UI (preview + expand button vs. plain textarea)

Field Configuration

• Updated LongTextOptions component to include the new LongTextShowAs selector
• Properly spreads existing options when updating to preserve other field settings

Internationalization

• Added translations for "Plain text" and "Markdown" labels across all supported languages (EN, DE, ES, FR, IT, JA, RU, TR, UK, ZH)

Cell Editor Integration

• Updated CellEditorMain to pass field options to the long text editor
• Editor now respects the showAs configuration to render appropriate UI

Implementation Details

• Markdown rendering uses existing MarkdownPreview component
• Image uploads are handled through AttachmentManager with proper attachment ID generation
• Editor maintains local state for unsaved changes with cancel/save functionality
• Fullscreen mode available for better editing experience on large content
• Readonly mode properly disables all editing controls

https://claude.ai/code/session_01UeuVodegDcLtwLKhTvfvHH

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[emilienbidet]

I will test it tonight