feat: Eino nodes 迁移到 trace 包（Phase 6.2）

- nodes_stt.go 使用 trace.FromContext 替换 logger.Log
- nodes_history.go 使用 trace.FromContext
- nodes_tts.go 使用 trace.FromContext
- nodes_done.go 使用 trace.FromContext
- 移除所有 nodes 中的 request_id 手动字段（自动附加）
- 所有日志消息改为英文

backend/internal/eino/nodes_stt.go

@@ -8,8 +8,8 @@ import (
 	"github.com/cloudwego/eino/compose"
 
 	"github.com/hhs/camtalk/internal/ai/stt"
-	"github.com/hhs/camtalk/internal/logger"
 	"github.com/hhs/camtalk/internal/models"
+	"github.com/hhs/camtalk/internal/trace"
 	"github.com/hhs/camtalk/internal/util"
 )
 
@@ -21,7 +21,7 @@ import (
 // 识别结果通过 Sender 发送 stt_result 到客户端。
 func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 	return compose.InvokableLambda(func(ctx context.Context, input PipelineInput) (STTOutput, error) {
-		log := logger.Log
+		log := trace.FromContext(ctx)
 		sender := senderFromCtx(ctx)
 		requestID := requestIDFromCtx(ctx)
 
@@ -41,7 +41,6 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 		// 文本输入模式：跳过 STT
 		if input.Text != "" {
 			log.Debugw("text input mode, skipping stt",
-				"request_id", requestID,
 				"text_len", len(input.Text),
 				"text_preview", util.Truncate(input.Text, 50))
 
@@ -53,7 +52,7 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 					Text:      input.Text,
 					IsFinal:   true,
 				}); err != nil {
-					log.Errorw("发送 stt_result 失败", "error", err)
+					log.Errorw("send stt_result failed", "error", err)
 				}
 			}
 
@@ -76,8 +75,7 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 			return STTOutput{}, fmt.Errorf("stt: no audio data provided")
 		}
 
-		log.Infow("开始语音识别",
-			"request_id", requestID, "audio_bytes", len(input.AudioData))
+		log.Infow("stt recognition started", "audio_bytes", len(input.AudioData))
 
 		// 调用 STT 服务
 		text, err := sttService.Recognize(ctx, input.AudioData, stt.Options{
@@ -86,7 +84,7 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 			Language:   input.Language,
 		})
 		if err != nil {
-			log.Errorw("语音识别失败", "error", err, "request_id", requestID)
+			log.Errorw("stt recognition failed", "error", err)
 			if sender != nil {
 				sender.SendError(models.WsError{
 					Type:      "error",
@@ -100,12 +98,11 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 
 		// STT 返回空文本
 		if strings.TrimSpace(text) == "" {
-			log.Infow("语音识别结果为空", "request_id", requestID)
+			log.Infow("stt returned empty text")
 			text = "（未识别到语音）"
 		}
 
 		log.Debugw("stt recognition completed",
-			"request_id", requestID,
 			"text_len", len(text),
 			"text_preview", util.Truncate(text, 50))
 
@@ -117,7 +114,7 @@ func NewSTTLambda(sttService stt.Service) *compose.Lambda {
 				Text:      text,
 				IsFinal:   true,
 			}); err != nil {
-				log.Errorw("发送 stt_result 失败", "error", err)
+				log.Errorw("send stt_result failed", "error", err)
 			}
 		}