fix(gemini): 移除空返图占位并暴露失败原因

Gemini 图片响应未包含可提取资源时，不再返回伪造占位图，改为非重试失败并保留安全拦截、候选结束状态和上游错误等结构化诊断。\n\n同步将诊断写入 HTTP 错误、任务结果、attempt 指标和日志，确保任务失败时不结算，并补充单元及 PostgreSQL 验收测试。\n\n验证：gofmt、go test ./... -count=1、go vet ./...、迁移安全检查、pnpm openapi。

apps/api/internal/runner/recording.go

@@ -258,6 +258,9 @@ func failureMetrics(err error, simulated bool) (string, map[string]any, time.Tim
 		metrics["error"] = err.Error()
 		metrics["errorCategory"] = info.Category
 		metrics["retryable"] = retryable
+		if details := clients.ErrorDetails(err); len(details) > 0 {
+			metrics["errorDetails"] = details
+		}
 		if detail := rateLimitFailureDetail(err); len(detail) > 0 {
 			metrics["rateLimit"] = detail
 		}
@@ -288,6 +291,9 @@ func buildFailureResult(code string, message string, requestID string, err error
 	if requestID != "" {
 		errorPayload["requestId"] = requestID
 	}
+	if details := clients.ErrorDetails(err); len(details) > 0 {
+		errorPayload["details"] = details
+	}
 	if detail := rateLimitFailureDetail(err); len(detail) > 0 {
 		errorPayload["rateLimit"] = detail
 	}

apps/api/internal/runner/recording_test.go

@@ -3,6 +3,7 @@ package runner
 import (
 	"testing"
 
+	"github.com/easyai/easyai-ai-gateway/apps/api/internal/clients"
 	"github.com/easyai/easyai-ai-gateway/apps/api/internal/store"
 )
 
@@ -45,3 +46,27 @@ func TestAttemptMetricsIncludesCacheAffinityCoefficient(t *testing.T) {
 		t.Fatalf("expected cache affinity routing diagnostics in attempt metrics, got %+v", metrics)
 	}
 }
+
+func TestFailureRecordIncludesStructuredClientErrorDetails(t *testing.T) {
+	cause := &clients.ClientError{
+		Code:    "gemini_image_output_missing",
+		Message: "Gemini image response contains no extractable image: prompt blocked",
+		Details: map[string]any{
+			"provider":          "gemini",
+			"reason":            "prompt_blocked",
+			"promptBlockReason": "SAFETY",
+		},
+	}
+
+	_, metrics, _, _, _ := failureMetrics(cause, false)
+	details, _ := metrics["errorDetails"].(map[string]any)
+	if details["reason"] != "prompt_blocked" || details["promptBlockReason"] != "SAFETY" {
+		t.Fatalf("failure metrics lost client error details: %+v", metrics)
+	}
+	result := buildFailureResult(cause.Code, cause.Message, "", cause)
+	errorPayload, _ := result["error"].(map[string]any)
+	resultDetails, _ := errorPayload["details"].(map[string]any)
+	if resultDetails["provider"] != "gemini" || resultDetails["reason"] != "prompt_blocked" {
+		t.Fatalf("failure result lost client error details: %+v", result)
+	}
+}

apps/api/internal/runner/service.go

@@ -1412,6 +1412,20 @@ func (s *Service) runCandidate(
 			response.ResponseDurationMS = 0
 		}
 	}
+	if err != nil && clients.ErrorCode(err) == "gemini_image_output_missing" && s.logger != nil {
+		meta := clients.ErrorResponseMetadata(err)
+		s.logger.Warn("gemini image response contains no extractable resource",
+			"taskID", task.ID,
+			"attempt", attemptNo,
+			"platformID", candidate.PlatformID,
+			"platformModelID", candidate.PlatformModelID,
+			"clientID", candidate.ClientID,
+			"requestID", meta.RequestID,
+			"error_category", clients.ErrorCode(err),
+			"reason", err.Error(),
+			"details", clients.ErrorDetails(err),
+		)
+	}
 	if err != nil {
 		if clients.ErrorResponseMetadata(err).StatusCode > 0 && submissionStatus != "response_received" {
 			if markErr := setSubmissionStatus("response_received"); markErr != nil {