feat: Computer Use — Windows 跨平台支持 + GUI 无障碍增强 + Python Bridge

三平台 Computer Use (macOS + Windows + Linux)，Windows 专项增强。

- MCP server: toolCalls/tools/executor/mcpServer 等 12 文件完整实现
- 平台抽象层: platforms/{win32,darwin,linux}.ts
- 跨平台 executor: executorCrossPlatform.ts
- CHICAGO_MCP + VOICE_MODE feature flags 启用

- windowMessage.ts: SendMessageW (WM_CHAR Unicode + 剪贴板粘贴)
- windowBorder.ts: 4 叠加窗口边框 (30fps 跟踪)
- uiAutomation.ts: UI Automation 元素树/点击/写值
- accessibilitySnapshot.ts: 无障碍快照 → 模型感知 GUI
- bridge.py + bridgeClient.ts: Python 长驻进程 (替代 per-call PS)

- window_management: min/max/restore/close/focus (Win32 API)
- click_element / type_into_element: 按名称操作 (无需坐标)
- 截图自动附带 Accessibility Snapshot

- 17 种方法, stdin/stdout JSON 通信
- 窗口枚举 1.5ms vs PS 500ms, 截图 360ms vs PS 800ms
- 依赖: mss + Pillow + pywinauto

src/utils/computerUse/platforms/index.ts

@@ -0,0 +1,41 @@
+/**
+ * Platform dispatcher for Computer Use.
+ *
+ * Loads the correct platform backend based on `process.platform`.
+ * Each backend implements the same unified interface.
+ */
+
+import type { InputPlatform, ScreenshotPlatform, DisplayPlatform, AppsPlatform, WindowManagementPlatform } from './types.js'
+
+export interface Platform {
+  input: InputPlatform
+  screenshot: ScreenshotPlatform
+  display: DisplayPlatform
+  apps: AppsPlatform
+  windowManagement?: WindowManagementPlatform
+}
+
+let cached: Platform | undefined
+
+export function loadPlatform(): Platform {
+  if (cached) return cached
+
+  switch (process.platform) {
+    case 'darwin':
+      cached = require('./darwin.js').platform
+      break
+    case 'win32':
+      cached = require('./win32.js').platform
+      break
+    case 'linux':
+      cached = require('./linux.js').platform
+      break
+    default:
+      throw new Error(`Computer Use not supported on ${process.platform}`)
+  }
+
+  return cached!
+}
+
+export type { InputPlatform, ScreenshotPlatform, DisplayPlatform, AppsPlatform, WindowManagementPlatform } from './types.js'
+export type { WindowHandle, ScreenshotResult, DisplayInfo, InstalledApp, FrontmostAppInfo, WindowAction } from './types.js'