fix(usage): 修复含失败信号的 pending 请求被误判为活跃的问题

- pending/streaming 状态含 status_code >= 400 或 error_message 时视为 failed
- 候选状态派生改为 failed 优先于 stale pending/streaming
- 活跃请求轮询时保留失败信号字段的更新
- 图片流支持 partial_image 事件转发及从 response.completed 读取最终图片

apps/aether-gateway/src/handlers/admin/observability/monitoring/tests/trace.rs

@@ -76,6 +76,51 @@ async fn admin_monitoring_trace_request_returns_local_payload() {
     assert_eq!(payload["candidates"][0]["status_code"], json!(502));
 }
 
+#[tokio::test]
+async fn admin_monitoring_trace_final_status_prefers_failed_over_stale_pending() {
+    let request_candidates = Arc::new(InMemoryRequestCandidateRepository::seed(vec![
+        sample_candidate(
+            "cand-stale-pending",
+            "request-1",
+            0,
+            RequestCandidateStatus::Pending,
+            None,
+            None,
+            None,
+        ),
+        sample_candidate(
+            "cand-failed",
+            "request-1",
+            1,
+            RequestCandidateStatus::Failed,
+            Some(101),
+            Some(33),
+            Some(502),
+        ),
+    ]));
+    let provider_catalog = Arc::new(InMemoryProviderCatalogReadRepository::seed(
+        vec![sample_provider()],
+        vec![sample_endpoint()],
+        vec![sample_key()],
+    ));
+    let state = AppState::new()
+        .expect("state should build")
+        .with_decision_trace_data_readers_for_tests(request_candidates, provider_catalog);
+    let context = request_context(http::Method::GET, "/api/admin/monitoring/trace/request-1");
+
+    let response = local_monitoring_response(&state, &context)
+        .await
+        .expect("handler should not error")
+        .expect("route should be handled locally");
+
+    assert_eq!(response.status(), http::StatusCode::OK);
+    let body = to_bytes(response.into_body(), usize::MAX)
+        .await
+        .expect("body should read");
+    let payload: serde_json::Value = serde_json::from_slice(&body).expect("json body should parse");
+    assert_eq!(payload["final_status"], json!("failed"));
+}
+
 #[tokio::test]
 async fn admin_monitoring_trace_request_keeps_format_conversion_disabled_candidates_visible() {
     let mut format_disabled_candidate = sample_candidate(

apps/aether-gateway/src/handlers/admin/observability/usage/summary_routes.rs

@@ -6,10 +6,11 @@ use crate::handlers::admin::shared::query_param_value;
 use crate::GatewayError;
 use aether_admin::observability::usage::{
     admin_usage_bad_request_response, admin_usage_data_unavailable_response,
-    admin_usage_has_fallback, admin_usage_matches_search, admin_usage_matches_username,
-    admin_usage_parse_ids, admin_usage_parse_limit, admin_usage_parse_offset,
-    build_admin_usage_active_requests_response, build_admin_usage_records_response,
-    build_admin_usage_summary_stats_response_from_summary, ADMIN_USAGE_DATA_UNAVAILABLE_DETAIL,
+    admin_usage_has_fallback, admin_usage_is_failed, admin_usage_matches_search,
+    admin_usage_matches_username, admin_usage_parse_ids, admin_usage_parse_limit,
+    admin_usage_parse_offset, build_admin_usage_active_requests_response,
+    build_admin_usage_records_response, build_admin_usage_summary_stats_response_from_summary,
+    ADMIN_USAGE_DATA_UNAVAILABLE_DETAIL,
 };
 use aether_data_contracts::repository::usage::{
     StoredRequestUsageAudit, UsageAuditKeywordSearchQuery, UsageAuditListQuery,
@@ -305,6 +306,14 @@ pub(super) async fn maybe_build_local_admin_usage_summary_response(
                     })
                     .await?
             };
+            let items = if requested_ids.is_some() {
+                items
+            } else {
+                items
+                    .into_iter()
+                    .filter(|item| !admin_usage_is_failed(item))
+                    .collect::<Vec<_>>()
+            };
             let api_key_names = admin_usage_api_key_names(state, &items).await?;
             let provider_key_names = admin_usage_provider_key_names(state, &items).await?;