feat: integrate markdown parsing into SuperDoc

[caio-pizzol]

No description provided.

[harbournick]

Looking good! just a minor comment to move convertMarkdownToHTML and prepareHTMLForSuperDoc to some helpers folder rather than making this Editor private methods. likely means the use of 'marked' will move to the helper and the import can be removed from Editor.js

Just an effort to keep this already huge class smaller!

[harbournick]

worth double checking if the copilot is right

[Copilot]

Pull Request Overview

This PR integrates markdown parsing functionality into SuperDoc, enabling users to upload and process markdown files alongside existing document formats. The implementation converts markdown to HTML internally and leverages existing HTML import capabilities.

Key changes:

• Added markdown file support to upload components (.md extension)
• Created markdown-to-HTML conversion utilities using the marked library
• Updated SuperDoc configuration handling to support markdown content
• Enhanced test coverage for markdown import functionality

Reviewed Changes

Copilot reviewed 18 out of 19 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
shared/common/components/BasicUpload.vue	Added .md to accepted file types
packages/superdoc/src/stores/superdoc-store.js	Added markdown config handling
packages/superdoc/src/dev/components/SuperdocDev.vue	Enhanced file handling for markdown and HTML files
packages/superdoc/src/core/SuperDoc.js	Added markdown property to JSDoc configuration
packages/superdoc/src/composables/use-document.js	Added markdown parameter support
packages/superdoc/src/SuperDoc.vue	Passed markdown property to editor options
packages/super-editor/src/core/helpers/importMarkdown.js	New markdown conversion utilities
packages/super-editor/src/core/helpers/importHtml.js	Extracted HTML import helper
packages/super-editor/src/core/Editor.js	Integrated markdown support into editor initialization
packages/super-editor/src/components/SuperEditor.vue	Enhanced file handling for non-DOCX files
packages/super-editor/src/core/super-converter/exporter.js	Added heading node export functionality
packages/super-editor/package.json	Added marked library dependency

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[harbournick]

All looks good but could you please add some unit tests (in the same folder, next to the file) for:
packages/super-editor/src/core/helpers/importHtml.js
packages/super-editor/src/core/helpers/importMarkdown.js

Also add // @ts-check at the top of these and verify any typing issues are working. Since these are small self-contained files we should be able to pass ts validation