阶段1-rpa-core建包: engine+31个纯Node能力迁入packages/rpa-core, 领域类型单一源化, createEngine工厂收拢模块级状态

- engine/(registry/types/runtime/expression)物理迁入包, 解耦shared/types(域类型归包, 宿主type-only re-export)
- 31个纯Node能力+27个测试迁入包; 宿主留守Electron/浏览器/AI依赖能力, index.ts经@rpa/core/capabilities拉起
- 新增createEngine()/defaultEngine: excel缓存/Excel句柄/db连接/FTP客户端/OCR实例/拟真设置挂引擎实例
- remaining-core子流程依赖改为host-bridge注入, 包内不再import宿主flows
- 宿主main/index.ts启动时注入子流程源; electron-vite/vitest/tsconfig配@rpa/core源码别名
- 验证: typecheck绿, 快照909个id diff为零, 332测试过(2个桌面冒烟因会话无交互SetForegroundWindow被拒, 环境阻塞)

package.json

@@ -4,6 +4,9 @@
   "private": true,
   "description": "Canvas-based RPA desktop application",
   "main": "./out/main/index.js",
+  "workspaces": [
+    "packages/*"
+  ],
   "scripts": {
     "dev": "electron-vite dev",
     "dev:local": "node scripts/dev-safe.mjs",