feat: ship v1.2.0 Wave 1 foundation with book settings, chapter management, and focus mode

Deliver schema v9, book/chapter IPC extensions, BookSettingsTab, chapter meta/tags,
AI session menu, focus mode and TTS, template context enrich, and Wave 1 E2E coverage.

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

e2e/focus-tts.spec.ts

@@ -0,0 +1,42 @@
+import { mkdtempSync, rmSync, existsSync } from 'fs'
+import { join } from 'path'
+import { tmpdir } from 'os'
+import { test, expect } from '@playwright/test'
+import { launchApp, skipOnboarding, createBookAndOpenEditor, ensureChapterEditor } from './helpers'
+
+test.describe('Focus mode', () => {
+  let userDataDir: string
+
+  test.beforeEach(() => {
+    userDataDir = mkdtempSync(join(tmpdir(), 'bilin-e2e-focus-'))
+  })
+
+  test.afterEach(() => {
+    if (userDataDir && existsSync(userDataDir)) {
+      try {
+        rmSync(userDataDir, { recursive: true, force: true, maxRetries: 3, retryDelay: 200 })
+      } catch {
+        /* ignore */
+      }
+    }
+  })
+
+  test('E2E-FOCUS-01: Ctrl+Alt+F enters focus mode, Esc exits', async () => {
+    const app = await launchApp(userDataDir)
+    const page = await app.firstWindow()
+    await skipOnboarding(page)
+    await createBookAndOpenEditor(page, '专注模式书')
+    await ensureChapterEditor(page)
+
+    await page.getByTestId('topbar-focus-mode').click()
+    await expect(page.getByTestId('app-root')).toHaveClass(/focus-mode/, { timeout: 5000 })
+    await expect(page.locator('#left-sidebar')).toBeHidden()
+    await expect(page.getByTestId('focus-mode-exit')).toBeVisible()
+
+    await page.keyboard.press('Escape')
+    await expect(page.getByTestId('app-root')).not.toHaveClass(/focus-mode/)
+    await expect(page.locator('#left-sidebar')).toBeVisible()
+
+    await app.close()
+  })
+})