feat(w3): ship v1.4.0 export matrix, cockpit tasks, and focus ambient

Add ExportMatrixService for txt/md/docx/pdf, extend ExportModal, cockpit outline tasks, focus ambient sound, and E2E-PDF-01 with 134 passing unit tests.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/main/export-content.test.ts

@@ -0,0 +1,25 @@
+import { describe, it, expect } from 'vitest'
+import { buildTxtExport, htmlToPlainParagraphs } from '../../src/main/lib/export-content'
+
+describe('export-content', () => {
+  it('htmlToPlainParagraphs splits paragraph tags', () => {
+    const html = '<p>第一段。</p><p>第二段。</p>'
+    expect(htmlToPlainParagraphs(html)).toEqual(['第一段。', '第二段。'])
+  })
+
+  it('buildTxtExport includes chapter title and AI marker', () => {
+    const txt = buildTxtExport([
+      {
+        id: '1',
+        title: '第一章',
+        volumeName: '卷一',
+        paragraphs: ['正文内容。'],
+        annotations: [],
+        hasAiContent: true
+      }
+    ])
+    expect(txt).toContain('# 第一章')
+    expect(txt).toContain('[AI生成内容]')
+    expect(txt).toContain('正文内容。')
+  })
+})