fix(provider): 延长媒体超时并终止超时轮转

将图像和视频的默认 HTTP/轮询超时分别提高到 20 分钟和 30 分钟。媒体任务超时后直接失败，不再重试、切换客户端或标记为 upstream_submission_unknown。OpenAI 图像端点遇到上游明确拒绝 response_format 时自动移除并缓存兼容结论。

验证：go test ./... -count=1；go vet ./...；gofmt；相关 Shell bash -n、ShellCheck 与发布脚本回归测试。

apps/api/internal/clients/openai.go

@@ -82,7 +82,8 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 	upstreamEndpoint := joinURL(openAIBaseURL(endpointKind, request.Candidate), endpoint)
 	responseStartedAt := time.Now()
 	correctionScope := newParameterCorrectionScope(request, endpointKind)
-	correctionEnabled := endpointKind == "chat.completions" || endpointKind == "responses"
+	correctionEnabled := endpointKind == "chat.completions" || endpointKind == "responses" ||
+		endpointKind == "images.generations" || endpointKind == "images.edits"
 	protectedCorrections := callerProtectedCorrectionParameters(request, endpointKind)
 	if correctionEnabled {
 		c.Corrections.apply(correctionScope, body, protectedCorrections)
@@ -108,7 +109,7 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 		}
 		resp, requestErr = requestClient.Do(req)
 		if requestErr != nil {
-			return Response{}, &ClientError{Code: "network", Message: requestErr.Error(), Retryable: true}
+			return Response{}, transportClientError(requestErr)
 		}
 		if err := notifyResponseReceived(request); err != nil {
 			_ = resp.Body.Close()