feat(voice): 阿里百炼 STT/TTS 主链路接通(base64 STT + cosyvoice TTS按voice_id + REST /audio/* + voice_input.deviceId)

- voice/dashscope.go 新建：DashscopeSTT(qwen-audio-3.0-asr-flash, base64 data URI→text) + DashscopeTTS(cosyvoice 按 voice_id, 取非流式 24h URL 下载字节)
- cloud.go newDashboardSTT/TTS 由空 endpoint stub 改为真实百炼 adapter
- chain.go gating 从 DashscopeAPIKey!="" 改为 voiceConfigured(cfg); silent 兜底保留
- config.VoiceConfig 扩展 DASHSCOPE_BASE_URL/VOICE_STT_*/VOICE_TTS_* 字段(必填 DASHSCOPE_API_KEY)
- gateway: POST /api/v1/audio/{transcribe,speech} (owner+审计+MaxBytesReader); voiceInputRequest 增 deviceId 并透传 runner.Run
- 实测: cosyvoice-v3.5-plus+longxiaochun 回 418(引擎拒绝), 改用 cosyvoice-v3-flash+longxiaochun_v3; TTS 你好我是昔涟->106124B wav -> STT 回 你好我是西联, 链返回真实字节/文本
- 单测: dashscope_test/config voice defaults/gateway audio_test; go build/vet/test 全绿
- 声音复刻(响昔涟音色)待公网参考音频; 不做 create_voice

internal/services/gateway/voice.go

@@ -26,12 +26,14 @@ type VoiceService interface {
 // voiceInputRequest is the decoded payload of a voice_input frame. Audio is a
 // base64 (or data: URI) audio blob; Format is its encoding ("wav"/"mp3"/"ogg");
 // Text overrides STT when present (a client that already transcribed can skip
-// recognition); SessionID defaults to "web".
+// recognition); SessionID defaults to "web"; DeviceID is the client-produced
+// end identifier (design/16 §4.5) threaded into the persisted voice turn.
 type voiceInputRequest struct {
 	Audio     string `json:"audio"`
 	Format    string `json:"format"`
 	Text      string `json:"text"`
 	SessionID string `json:"sessionId"`
+	DeviceID  string `json:"deviceId,omitempty"`
 }
 
 // SetVoice injects the voice STT/TTS service used by the voice_input WS route.
@@ -66,6 +68,9 @@ func (c *wsConn) handleVoiceInput(in wsInbound) {
 // carrying the base64 audio plus the recognized transcript and assistant reply.
 func (h *hub) runVoiceTurn(c *wsConn, req voiceInputRequest) {
 	ctx := context.Background()
+	// Thread the client's deviceID so the persisted voice turn is tagged with the
+	// sending end (design/16 §4.5), mirroring ws_hub.go:240.
+	ctx = withDeviceID(ctx, req.DeviceID)
 	if req.SessionID == "" {
 		req.SessionID = "web"
 	}