fix(web): resolve duplicate tiptap Link extension warning

Disable Link in StarterKit since it's configured separately.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/components/common/rich-text-editor.tsx

@@ -141,6 +141,7 @@ const RichTextEditor = forwardRef<RichTextEditorRef, RichTextEditorProps>(
       extensions: [
         StarterKit.configure({
           heading: { levels: [1, 2, 3] },
+          link: false,
         }),
         Placeholder.configure({
           placeholder: placeholderText,