refactor(*): 平台架构 - 拆分后端领域模块并同步插件协议与模型能力

backend/internal/app/text_stream_usage.go

@@ -0,0 +1,37 @@
+package app
+
+import (
+	"encoding/json"
+	"errors"
+)
+
+// EnsureChatCompletionStreamUsageRequest 为 Token 计费的流式 Chat Completions
+// 请求开启最终 usage 块；非流式请求保持原样，避免改变普通接口合同。
+func EnsureChatCompletionStreamUsageRequest(data []byte) ([]byte, error) {
+	var payload map[string]any
+	if err := json.Unmarshal(data, &payload); err != nil {
+		return nil, err
+	}
+	stream, _ := payload["stream"].(bool)
+	if !stream {
+		return data, nil
+	}
+	if err := ensureChatCompletionStreamUsage(payload); err != nil {
+		return nil, err
+	}
+	return json.Marshal(payload)
+}
+
+func ensureChatCompletionStreamUsage(payload map[string]any) error {
+	options := map[string]any{}
+	if value, exists := payload["stream_options"]; exists {
+		var ok bool
+		options, ok = value.(map[string]any)
+		if !ok {
+			return errors.New("stream_options 必须是 JSON 对象")
+		}
+	}
+	options["include_usage"] = true
+	payload["stream_options"] = options
+	return nil
+}