fix(editor): keep rich mode for documents with details blocks

The markdown serializer always injected class="orca-details" into
saved <details> tags. The rich-mode round-trip check compares the
serialized output against the source's literal opening tag, so any
user-authored <details> without that class failed the comparison and
fell back to Source mode, making the details extension unreachable
from a file. The class is already applied to the rendered DOM node
independently, so the serializer no longer needs to write it into the
markdown source.

src/renderer/src/components/editor/details-markdown-html.ts

@@ -78,8 +78,11 @@ export function detailsBodyHtmlToMarkdown(body: string): string {
     .trim()
 }
 
+// Why: the styling class is applied to the rendered DOM node independently
+// (OrcaDetails' HTMLAttributes config), so writing it into the markdown
+// source would rewrite a user's plain `<details>` on every save.
 export function renderDetailsAttributes(attrs: Record<string, unknown> | undefined): string {
-  const attributes = ['class="orca-details"']
+  const attributes: string[] = []
 
   const variant = parseToggleHeadingVariant(attrs?.variant)
   if (variant) {

src/renderer/src/components/editor/markdown-rich-mode.test.ts

@@ -168,6 +168,58 @@ describe('getMarkdownRichModeUnsupportedMessage', () => {
     expect(usedGlobalHtmlFragmentMatch).toBe(false)
   })
 
+  it('allows a minimal bare details block with no pre-existing styling class', () => {
+    expect(
+      getMarkdownRichModeUnsupportedMessage('<details><summary>x</summary>\n\nbody\n\n</details>\n')
+    ).toBeNull()
+  })
+
+  it('allows a minimal bare details block with the open attribute', () => {
+    expect(
+      getMarkdownRichModeUnsupportedMessage(
+        '<details open><summary>x</summary>\n\nbody\n\n</details>\n'
+      )
+    ).toBeNull()
+  })
+
+  it('allows a document with front matter, prose, and two details blocks', () => {
+    const content = [
+      '---',
+      'title: Details Disclosure Test',
+      '---',
+      '',
+      '# Heading',
+      '',
+      'Some prose before the first toggle.',
+      '',
+      '<details>',
+      '<summary>First toggle</summary>',
+      '',
+      '**Bold text** and a [link](./target%20file.md).',
+      '',
+      '- one',
+      '- two',
+      '',
+      '```ts',
+      'const answer = 42',
+      '```',
+      '',
+      '</details>',
+      '',
+      'A paragraph between the two toggles.',
+      '',
+      '<details open>',
+      '<summary>Second toggle</summary>',
+      '',
+      'Short body.',
+      '',
+      '</details>',
+      ''
+    ].join('\n')
+
+    expect(getMarkdownRichModeUnsupportedMessage(content)).toBeNull()
+  })
+
   it('keeps unsupported content blocked when it also exceeds the size limit', () => {
     const content = `${'a'.repeat(RICH_MARKDOWN_MAX_SIZE_BYTES + 1)}<Widget />`
 

src/renderer/src/components/editor/rich-markdown-details-extension.ts

@@ -282,8 +282,9 @@ const OrcaDetails = Details.extend({
     )
     const body = helpers.renderChildren(content?.content ?? [], '\n\n').trim()
     const attrs = renderDetailsAttributes(node.attrs)
+    const openingTag = attrs ? `<details ${attrs}>` : '<details>'
 
-    return `<details ${attrs}>\n<summary>${summaryText}</summary>\n\n${body}\n\n</details>`
+    return `${openingTag}\n<summary>${summaryText}</summary>\n\n${body}\n\n</details>`
   }
 })
 

src/renderer/src/components/editor/rich-markdown-details-keyboard.test.ts

@@ -90,12 +90,12 @@ describe('rich markdown details keyboard behavior', () => {
     [
       'text toggle',
       '<details><summary>Toggle</summary><p></p></details>',
-      '<details class="orca-details">\n<summary>Toggle</summary>\n\n\n\n</details>'
+      '<details>\n<summary>Toggle</summary>\n\n\n\n</details>'
     ],
     [
       'heading toggle',
       '<details data-orca-toggle="heading-1"><summary>Toggle</summary><p></p></details>',
-      '<details class="orca-details" data-orca-toggle="heading-1">\n<summary>Toggle</summary>\n\n\n\n</details>'
+      '<details data-orca-toggle="heading-1">\n<summary>Toggle</summary>\n\n\n\n</details>'
     ]
   ])('moves backspace from an empty %s body to the summary', (_name, content, expected) => {
     const editor = createEditor(content)