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>

src/utils/imagePaste.ts

@@ -106,10 +106,10 @@ export async function hasImageInClipboard(): Promise<boolean> {
     // as an unhandled rejection in useClipboardImageHint's setTimeout.
     try {
       const { getNativeModule } = await import('image-processor-napi')
-      const nativeModule = getNativeModule() as Record<string, Function> | null
-      const hasImage = nativeModule?.hasClipboardImage
-      if (hasImage) {
-        return hasImage()
+      const nativeModule = getNativeModule()
+      if (nativeModule && 'hasClipboardImage' in nativeModule) {
+        const hasImage = (nativeModule as unknown as Record<string, Function>).hasClipboardImage
+        if (hasImage) return hasImage()
       }
     } catch (e) {
       logError(e as Error)
@@ -136,8 +136,10 @@ export async function getImageFromClipboard(): Promise<ImageWithDimensions | nul
   ) {
     try {
       const { getNativeModule } = await import('image-processor-napi')
-      const nativeModule = getNativeModule() as Record<string, Function> | null
-      const readClipboard = nativeModule?.readClipboardImage
+      const nativeModule = getNativeModule()
+      const readClipboard = nativeModule && 'readClipboardImage' in nativeModule
+        ? (nativeModule as unknown as Record<string, Function>).readClipboardImage
+        : undefined
       if (!readClipboard) {
         throw new Error('native clipboard reader unavailable')
       }