fix: 修复表单相册上传失败bug，优化FormData构造方式

- 移除uploadFile.ts中不必要的Platform判断逻辑
- 保持原始URI不做修改，让React Native底层处理平台差异
- 添加uploadFile单元测试，覆盖主要上传场景
- 简化代码结构，提高可维护性

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/uploadFile.ts

@@ -6,13 +6,12 @@ import { handleError } from '@/hooks/use-error'
 
 export async function uploadFile(params: { uri: string; mimeType?: string; fileName?: string }): Promise<string> {
   const { uri, mimeType, fileName } = params
-  const file = {
+  const formData = new FormData()
+  formData.append('file', {
+    uri: uri,
     name: fileName || 'uploaded_file.jpg',
     type: mimeType || 'image/jpeg',
-    uri: Platform.OS === 'android' ? uri : uri.replace('file://', ''),
-  }
-  const formData = new FormData()
-  formData.append('file', file as any)
+  } as any)
 
   const fileController = root.get(FileController)
   const { data, error } = await handleError(async () => await fileController.uploadS3(formData))