feat: 实现笔临 P0/P1 Electron 桌面应用 v0.1.0

交付写作核心（TipTap、自动保存、分卷分章）、Onboarding、7 主题与双语 i18n、快捷键设置；主进程使用 node:sqlite；补全 Vitest 与 Playwright E2E；统一 design/ 目录并移除 desigin 拼写错误路径。

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

vitest.config.ts

@@ -0,0 +1,14 @@
+import { defineConfig } from 'vitest/config'
+import { resolve } from 'path'
+
+export default defineConfig({
+  test: {
+    environment: 'node',
+    include: ['tests/**/*.test.ts']
+  },
+  resolve: {
+    alias: {
+      '@shared': resolve('src/shared')
+    }
+  }
+})