refactor(config): 七牛/微信密钥外置——AK/SK+微信AppID 入本地 app_config, domain/bucket 走远程配置

- app_config.json + AppConfig: qiniu_access_key/qiniu_secret_key/wechat_app_id/wechat_app_secret(扁平snake_case)
- RemoteConfig.VersionFields + audio_domain/audio_bucket(4层可携带), VersionDecision + audioDomain/audioBucket
- VersionResolver.resolve 复用 pickStr 解析 audioDomain/audioBucket(4层逐级回退)
- QiniuToken.uploadToken(accessKey,secretKey,bucket) 改传参,去掉硬编码常量
- AudioProvider.doUpload: AK/SK取本地配置, domain/bucket取远程配置(cfg.resolve), URL用远程domain
- WeChatApi.configure(appId) 注入AppID(去WX_APP_ID常量), EntryAbility.onCreate 从配置注入
- 更新 QiniuToken 单测传参

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

entry/src/test/QiniuToken.test.ets

@@ -5,16 +5,17 @@ import { util } from '@kit.ArkTS';
 export default function QiniuTokenTest() {
   describe('QiniuTokenTest', () => {
     it('token_has_three_parts_and_valid_policy', 0, async () => {
-      const token: string = await QiniuToken.uploadToken();
+      // AK/SK/bucket 现由调用方注入（本地 app_config + 远程 audio_bucket），单测用固定测试值
+      const token: string = await QiniuToken.uploadToken('AK_TEST', 'SK_TEST', 'bk_test');
       const parts: string[] = token.split(':');
       expect(parts.length).assertEqual(3);
-      expect(parts[0]).assertEqual('ngN3rFW1j8dn7ZGpATKl7mreaNmp2Ei_l9AIhkIf');
+      expect(parts[0]).assertEqual('AK_TEST');
       expect(parts[1].length).assertEqual(28);
       const helper = new util.Base64Helper();
       const std: string = parts[2].replace(/-/g, '+').replace(/_/g, '/');
       const decoded: Uint8Array = helper.decodeSync(std);
       const policy: string = String.fromCharCode.apply(null, Array.from(decoded));
-      expect(policy.indexOf('"scope":"gameaudio"') >= 0).assertTrue();
+      expect(policy.indexOf('"scope":"bk_test"') >= 0).assertTrue();
     });
   });
 }