fix: add usage field to OpenAI streaming response final chunk (#10)

proxy/handler.go

@@ -1204,6 +1204,11 @@ func (h *Handler) handleOpenAIStream(w http.ResponseWriter, account *config.Acco
 			"delta":         map[string]interface{}{},
 			"finish_reason": finishReason,
 		}},
+		"usage": map[string]int{
+			"prompt_tokens":     inputTokens,
+			"completion_tokens": outputTokens,
+			"total_tokens":      inputTokens + outputTokens,
+		},
 	}
 	data, _ := json.Marshal(chunk)
 	fmt.Fprintf(w, "data: %s\n\n", string(data))

proxy/translator.go

@@ -16,6 +16,8 @@ var modelMap = map[string]string{
 	"claude-sonnet-4.5":        "claude-sonnet-4.5",
 	"claude-haiku-4-5":         "claude-haiku-4.5",
 	"claude-haiku-4.5":         "claude-haiku-4.5",
+	"claude-opus-4-6":         "claude-opus-4.6",
+	"claude-opus-4.6":         "claude-opus-4.6",
 	"claude-opus-4-5":          "claude-opus-4.5",
 	"claude-opus-4.5":          "claude-opus-4.5",
 	"claude-sonnet-4":          "claude-sonnet-4",