feat(sora): 对齐 Sora OAuth 流程并隔离网关请求路径

- 新增并接通 Sora 专用 OAuth 接口与 ST/RT 换取能力
- 完成前端 Sora 授权、RT/ST 手动导入与账号创建流程
- 强化 Sora token 恢复、转发日志与网关路由隔离行为
- 补充后端服务层与路由层相关测试覆盖

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

backend/internal/service/wire.go

@@ -206,6 +206,18 @@ func ProvideSoraMediaStorage(cfg *config.Config) *SoraMediaStorage {
 	return NewSoraMediaStorage(cfg)
 }
 
+func ProvideSoraDirectClient(
+	cfg *config.Config,
+	httpUpstream HTTPUpstream,
+	tokenProvider *OpenAITokenProvider,
+	accountRepo AccountRepository,
+	soraAccountRepo SoraAccountRepository,
+) *SoraDirectClient {
+	client := NewSoraDirectClient(cfg, httpUpstream, tokenProvider)
+	client.SetAccountRepositories(accountRepo, soraAccountRepo)
+	return client
+}
+
 // ProvideSoraMediaCleanupService 创建并启动 Sora 媒体清理服务
 func ProvideSoraMediaCleanupService(storage *SoraMediaStorage, cfg *config.Config) *SoraMediaCleanupService {
 	svc := NewSoraMediaCleanupService(storage, cfg)
@@ -255,7 +267,7 @@ var ProviderSet = wire.NewSet(
 	NewGatewayService,
 	ProvideSoraMediaStorage,
 	ProvideSoraMediaCleanupService,
-	NewSoraDirectClient,
+	ProvideSoraDirectClient,
 	wire.Bind(new(SoraClient), new(*SoraDirectClient)),
 	NewSoraGatewayService,
 	NewOpenAIGatewayService,