feat: 实现 4 个 NAPI 包 — modifiers/image-processor/audio-capture/url-handler

- modifiers-napi: 使用 Bun FFI 调用 macOS CGEventSourceFlagsState 检测修饰键
- image-processor-napi: 集成 sharp 库，macOS 剪贴板图像读取 (osascript)
- audio-capture-napi: 基于 SoX/arecord 的跨平台音频录制
- url-handler-napi: 完善函数签名（保持 null fallback）
- 修复 image-processor 类型兼容性问题

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/image-processor-napi/package.json

@@ -4,5 +4,8 @@
     "private": true,
     "type": "module",
     "main": "./src/index.ts",
-    "types": "./src/index.ts"
+    "types": "./src/index.ts",
+    "dependencies": {
+        "sharp": "^0.33.5"
+    }
 }