feat(录音): 七牛 uploadToken 端侧生成(HMAC-SHA1,对齐原工程不走服务端) + 结构单测

新增 platform/src/main/ets/upload/QiniuToken.ets：
- QiniuToken.uploadToken() 异步生成 uploadToken（deadline=now+1h）
- HMAC-SHA1 via cryptoFramework.createMac('SHA1')，对齐原 Android 硬编码 AK/SK
- urlsafeBase64 工具方法（util.Base64Helper.encodeToStringSync + 替换+/-/_）
- eslint-disable-next-line @security/no-unsafe-mac 注释说明七牛协议强制要求
platform/Index.ets 导出 QiniuToken。
entry/src/test/QiniuToken.test.ets 结构单测（三段token格式/AK/scope验证）。
List.test.ets 注册 QiniuTokenTest。

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

platform/Index.ets

@@ -15,3 +15,4 @@ export { Unzipper } from './src/main/ets/zip/Unzipper';
 export { PermissionGuard } from './src/main/ets/perm/PermissionGuard';
 export { LocalUploadServer } from './src/main/ets/upload/LocalUploadServer';
 export { QiniuUploader, QiniuTokenProvider } from './src/main/ets/upload/QiniuUploader';
+export { QiniuToken } from './src/main/ets/upload/QiniuToken';