fix(editor): disable StarterKit Link to prevent duplicate extension warning

[aculich]

Summary

Fixes console warning: "Duplicate extension names found: ['link']"

Fixes #433

Problem

StarterKit v3.x now includes the Link extension by default. The codebase separately adds Link.configure() with custom settings (openOnClick: false, custom HTMLAttributes), resulting in two Link extensions being registered.

This causes:

• Console warning spam on every editor mount
• Unpredictable behavior when two extensions share a name
• Configuration conflicts between StarterKit's Link defaults and the custom settings

Solution

Add link: false to StarterKit configuration to disable its built-in Link, allowing the custom-configured Link to be used exclusively.

Changes

• apps/x/apps/renderer/src/components/markdown-editor.tsx:
  • Added link: false to StarterKit.configure() options

Testing

1. Start the app
2. Open a markdown file
3. Verify no "Duplicate extension names" warning in console
4. Test link functionality:
   • Links should not open on click (custom behavior)
   • Links should have correct rel and target attributes

[vercel]

@aculich is attempting to deploy a commit to the RowBoat Labs Team on Vercel.

A member of the Team first needs to authorize it.

[Bortlesboat]

I checked the diff here against #433 and this is about as small as it gets: disable StarterKit's built-in Link so the existing Link.configure(...) is the only one registered.

If the duplicate-extension warning still reproduces on current main, this looks low-risk enough to merge after a quick editor smoke test:

• open a note
• confirm the warning is gone
• confirm link click behavior is still the custom one