feat(observability): 引入错误链路 error_flow 元数据并区分上游/客户端错误

- 网关在本地 failover 时构建 error_flow 元数据（分类/决策/传播策略），写入 report_context
- scheduler-core 解析并透传 error_flow 至候选 extra_data
- admin usage 详情拆分 request/upstream/client/failure_summary 错误域，敏感上游错误标记为 suppressed
- 前端 RequestDetailDrawer 拆出"返回客户端"与"上游响应"双错误卡片
- HorizontalRequestTimeline 节点详情展示真实请求错误及 error_flow 标签

apps/aether-gateway/src/execution_runtime/stream/execution.rs

@@ -70,10 +70,10 @@ use crate::execution_runtime::{
 use crate::execution_runtime::{MAX_STREAM_PREFETCH_BYTES, MAX_STREAM_PREFETCH_FRAMES};
 use crate::log_ids::short_request_id;
 use crate::orchestration::{
-    apply_local_execution_effect, LocalAdaptiveRateLimitEffect, LocalAdaptiveSuccessEffect,
-    LocalAttemptFailureEffect, LocalExecutionEffect, LocalExecutionEffectContext,
-    LocalHealthFailureEffect, LocalHealthSuccessEffect, LocalOAuthInvalidationEffect,
-    LocalPoolErrorEffect,
+    apply_local_execution_effect, build_local_error_flow_metadata, with_error_flow_report_context,
+    LocalAdaptiveRateLimitEffect, LocalAdaptiveSuccessEffect, LocalAttemptFailureEffect,
+    LocalExecutionEffect, LocalExecutionEffectContext, LocalHealthFailureEffect,
+    LocalHealthSuccessEffect, LocalOAuthInvalidationEffect, LocalPoolErrorEffect,
 };
 use crate::request_candidate_runtime::{
     ensure_execution_request_candidate_slot, record_local_request_candidate_status,
@@ -893,10 +893,20 @@ async fn execute_stream_from_frame_stream(
         );
         if matches!(failover_decision, LocalFailoverDecision::RetryNextCandidate) {
             let terminal_unix_secs = current_request_candidate_unix_ms();
+            let error_flow_report_context = with_error_flow_report_context(
+                report_context.as_ref(),
+                build_local_error_flow_metadata(
+                    status_code,
+                    error_response_text.as_deref(),
+                    failover_analysis,
+                ),
+            );
             record_local_request_candidate_status(
                 state,
                 &plan,
-                report_context.as_ref(),
+                error_flow_report_context
+                    .as_ref()
+                    .or(report_context.as_ref()),
                 SchedulerRequestCandidateStatusUpdate {
                     status: RequestCandidateStatus::Failed,
                     status_code: Some(status_code),
@@ -934,10 +944,20 @@ async fn execute_stream_from_frame_stream(
             )
         {
             let terminal_unix_secs = current_request_candidate_unix_ms();
+            let error_flow_report_context = with_error_flow_report_context(
+                report_context.as_ref(),
+                build_local_error_flow_metadata(
+                    status_code,
+                    error_response_text.as_deref(),
+                    failover_analysis,
+                ),
+            );
             record_local_request_candidate_status(
                 state,
                 &plan,
-                report_context.as_ref(),
+                error_flow_report_context
+                    .as_ref()
+                    .or(report_context.as_ref()),
                 SchedulerRequestCandidateStatusUpdate {
                     status: RequestCandidateStatus::Failed,
                     status_code: Some(status_code),
@@ -970,10 +990,20 @@ async fn execute_stream_from_frame_stream(
         );
         record_sync_terminal_usage(state, &plan, payload.report_context.as_ref(), &payload);
         let terminal_unix_secs = current_request_candidate_unix_ms();
+        let error_flow_report_context = with_error_flow_report_context(
+            payload.report_context.as_ref(),
+            build_local_error_flow_metadata(
+                status_code,
+                error_response_text.as_deref(),
+                failover_analysis,
+            ),
+        );
         record_local_request_candidate_status(
             state,
             &plan,
-            payload.report_context.as_ref(),
+            error_flow_report_context
+                .as_ref()
+                .or(payload.report_context.as_ref()),
             SchedulerRequestCandidateStatusUpdate {
                 status: RequestCandidateStatus::Failed,
                 status_code: Some(status_code),

apps/aether-gateway/src/execution_runtime/sync/execution.rs

@@ -35,10 +35,10 @@ use crate::execution_runtime::{
 };
 use crate::log_ids::short_request_id;
 use crate::orchestration::{
-    apply_local_execution_effect, LocalAdaptiveRateLimitEffect, LocalAdaptiveSuccessEffect,
-    LocalAttemptFailureEffect, LocalExecutionEffect, LocalExecutionEffectContext,
-    LocalHealthFailureEffect, LocalHealthSuccessEffect, LocalOAuthInvalidationEffect,
-    LocalPoolErrorEffect,
+    apply_local_execution_effect, build_local_error_flow_metadata, with_error_flow_report_context,
+    LocalAdaptiveRateLimitEffect, LocalAdaptiveSuccessEffect, LocalAttemptFailureEffect,
+    LocalExecutionEffect, LocalExecutionEffectContext, LocalHealthFailureEffect,
+    LocalHealthSuccessEffect, LocalOAuthInvalidationEffect, LocalPoolErrorEffect,
 };
 use crate::request_candidate_runtime::{
     ensure_execution_request_candidate_slot, record_local_request_candidate_status,
@@ -426,10 +426,20 @@ pub(crate) async fn execute_execution_runtime_sync(
         LocalFailoverDecision::RetryNextCandidate
     ) {
         let terminal_unix_secs = current_request_candidate_unix_ms();
+        let error_flow_report_context = with_error_flow_report_context(
+            report_context.as_ref(),
+            build_local_error_flow_metadata(
+                result.status_code,
+                local_failover_response_text.as_deref(),
+                local_failover_analysis,
+            ),
+        );
         record_local_request_candidate_status(
             state,
             &plan,
-            report_context.as_ref(),
+            error_flow_report_context
+                .as_ref()
+                .or(report_context.as_ref()),
             SchedulerRequestCandidateStatusUpdate {
                 status: RequestCandidateStatus::Failed,
                 status_code: Some(result.status_code),
@@ -488,10 +498,20 @@ pub(crate) async fn execute_execution_runtime_sync(
         mapped_error_finalize_kind.is_some(),
     ) {
         let terminal_unix_secs = current_request_candidate_unix_ms();
+        let error_flow_report_context = with_error_flow_report_context(
+            report_context.as_ref(),
+            build_local_error_flow_metadata(
+                result.status_code,
+                local_failover_response_text.as_deref(),
+                local_failover_analysis,
+            ),
+        );
         record_local_request_candidate_status(
             state,
             &plan,
-            report_context.as_ref(),
+            error_flow_report_context
+                .as_ref()
+                .or(report_context.as_ref()),
             SchedulerRequestCandidateStatusUpdate {
                 status: RequestCandidateStatus::Failed,
                 status_code: Some(result.status_code),
@@ -507,10 +527,24 @@ pub(crate) async fn execute_execution_runtime_sync(
     }
 
     let terminal_unix_secs = current_request_candidate_unix_ms();
+    let error_flow_report_context = (result.status_code >= 400)
+        .then(|| {
+            with_error_flow_report_context(
+                report_context.as_ref(),
+                build_local_error_flow_metadata(
+                    result.status_code,
+                    local_failover_response_text.as_deref(),
+                    local_failover_analysis,
+                ),
+            )
+        })
+        .flatten();
     record_local_request_candidate_status(
         state,
         &plan,
-        report_context.as_ref(),
+        error_flow_report_context
+            .as_ref()
+            .or(report_context.as_ref()),
         SchedulerRequestCandidateStatusUpdate {
             status: if result.status_code >= 400 {
                 RequestCandidateStatus::Failed

apps/aether-gateway/src/orchestration/classifier.rs

@@ -145,6 +145,23 @@ pub(crate) enum LocalFailoverClassification {
     RetryUpstreamFailure,
 }
 
+impl LocalFailoverClassification {
+    pub(crate) const fn as_str(self) -> &'static str {
+        match self {
+            Self::UseDefault => "use_default",
+            Self::StopStatusCode => "stop_status_code",
+            Self::StopErrorPattern => "stop_error_pattern",
+            Self::StopSemanticClientError => "stop_semantic_client_error",
+            Self::RetrySuccessPattern => "retry_success_pattern",
+            Self::RetrySemanticCompatibilityError => "retry_semantic_compatibility_error",
+            Self::RetrySemanticRateLimit => "retry_semantic_rate_limit",
+            Self::RetrySemanticThinkingError => "retry_semantic_thinking_error",
+            Self::RetryStatusCode => "retry_status_code",
+            Self::RetryUpstreamFailure => "retry_upstream_failure",
+        }
+    }
+}
+
 pub(crate) fn classify_local_failover(
     policy: &LocalFailoverPolicy,
     input: LocalFailoverInput<'_>,

apps/aether-gateway/src/orchestration/mod.rs

@@ -1,4 +1,5 @@
 use aether_contracts::ExecutionPlan;
+use serde_json::{json, Value};
 
 use crate::AppState;
 
@@ -78,3 +79,43 @@ pub(crate) async fn resolve_local_failover_decision_for_attempt(
     .await
     .decision
 }
+
+pub(crate) fn build_local_error_flow_metadata(
+    status_code: u16,
+    response_text: Option<&str>,
+    analysis: LocalFailoverAnalysis,
+) -> Value {
+    let safe_to_expose = matches!(
+        analysis.classification,
+        LocalFailoverClassification::StopSemanticClientError
+            | LocalFailoverClassification::StopStatusCode
+            | LocalFailoverClassification::StopErrorPattern
+    );
+    let propagation = match analysis.decision {
+        LocalFailoverDecision::RetryNextCandidate => "suppressed",
+        LocalFailoverDecision::StopLocalFailover if safe_to_expose => "converted",
+        LocalFailoverDecision::StopLocalFailover => "suppressed",
+        LocalFailoverDecision::UseDefault if status_code >= 400 => "passthrough",
+        LocalFailoverDecision::UseDefault => "none",
+    };
+    json!({
+        "stage": "candidate",
+        "source": "upstream_response",
+        "status_code": status_code,
+        "classification": analysis.classification.as_str(),
+        "decision": analysis.decision.as_str(),
+        "retryable": matches!(analysis.decision, LocalFailoverDecision::RetryNextCandidate),
+        "safe_to_expose": safe_to_expose,
+        "propagation": propagation,
+        "message": local_failover_error_message(response_text),
+    })
+}
+
+pub(crate) fn with_error_flow_report_context(
+    report_context: Option<&Value>,
+    error_flow: Value,
+) -> Option<Value> {
+    let mut object = report_context?.as_object()?.clone();
+    object.insert("error_flow".to_string(), error_flow);
+    Some(Value::Object(object))
+}