refactor: OpenAI TTS 使用 trace.FromContext 支持追踪

backend/internal/ai/tts/openai.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"time"
 
+	"github.com/hhs/camtalk/internal/trace"
 	"github.com/hhs/camtalk/internal/util"
 	"go.uber.org/zap"
 )
@@ -82,7 +83,8 @@ func (o *OpenAIService) SynthesizeStream(ctx context.Context, textStream <-chan
 
 			audio, err := o.synthesize(ctx, text, voice, speed)
 			if err != nil {
-				o.logger.Warnw("tts: synthesize failed",
+				log := trace.FromContext(ctx)
+				log.Warnw("tts: synthesize failed",
 					"error", err,
 					"text_len", len(text),
 					"text_preview", util.Truncate(text, 100))