feat: add Responses API compatibility

apps/api/internal/runner/recording.go

@@ -70,6 +70,15 @@ func taskMetrics(task store.GatewayTask, user *auth.User, body map[string]any, c
 	if response.ResponseDurationMS > 0 {
 		metrics["responseDurationMs"] = response.ResponseDurationMS
 	}
+	if response.UpstreamProtocol != "" {
+		metrics["upstreamProtocol"] = response.UpstreamProtocol
+		metrics["upstreamEndpoint"] = response.UpstreamEndpoint
+		metrics["responseConverted"] = response.ResponseConverted
+		metrics["publicResponseId"] = response.PublicResponseID
+		metrics["upstreamResponseId"] = response.UpstreamResponseID
+		metrics["parentResponseId"] = response.ParentResponseID
+		metrics["responseChainDepth"] = response.ResponseChainDepth
+	}
 	switch task.Kind {
 	case "chat.completions", "responses":
 		metrics["stream"] = boolFromMap(body, "stream")
@@ -119,6 +128,16 @@ func attemptMetrics(candidate store.RuntimeModelCandidate, attemptNo int, simula
 		"loadAvoided":      candidate.LoadAvoided,
 		"simulated":        simulated,
 	}
+	if candidate.ResponseProtocol != "" {
+		metrics["upstreamProtocol"] = candidate.ResponseProtocol
+		if candidate.ResponseProtocol == clients.ProtocolOpenAIResponses {
+			metrics["upstreamEndpoint"] = "/responses"
+			metrics["responseConverted"] = false
+		} else if candidate.ResponseProtocol == clients.ProtocolOpenAIChatCompletions {
+			metrics["upstreamEndpoint"] = "/chat/completions"
+			metrics["responseConverted"] = true
+		}
+	}
 	if candidate.LoadLimited {
 		metrics["loadMetrics"] = map[string]any{
 			"rpm": map[string]any{