feat(channelbridge): 出站语音结论落 voice 列并挂出站 Media（M58）

- voice.Ref 增 SourceTTS 与 FallbackReason，Validate/IsZero/validSource 同步
- 出站成功：INSERT -> 补写 voice 列 -> notify（首帧即带 voice）
- 出站降级：source=tts + status=failed + fallbackReason，正文原样
- 首条气泡挂出站 Media（新开条目，不复制 target.Media）
- gateway historyVoice 投影 fallbackReason
- 新增 outbound_voice.go 与整链 e2e 测试（含变异打红验证时序）

internal/services/channelbridge/inbound.go

@@ -193,15 +193,31 @@ func (b *Bridge) deliverReply(ctx context.Context, msg adapter.UnifiedMessage, a
 	if res != nil {
 		mood = res.Mood
 	}
+	// 出站语音（design/25 §7.1）：先把结算结论折成 voice 列事实，再让落库那条路走
+	// 「INSERT → 写 voice 列 → notify」（M44 首帧纪律）—— 与入站语音共用同一份
+	// persistVoiceFirstNotify，因此首帧上就带着 `voice`，客户端不必等重连。
+	ref, hasVoice := b.outboundVoiceRef(resultVoice(res))
+	notify := b.notifyPersisted
+	if hasVoice {
+		notify = b.persistVoiceFirstNotify(ref)
+	}
 	// 持久化助手回复（主人私聊 → 主会话 + message_persisted
 	// 广播；受限 → 隔离日志 + channel_persisted 广播），随后
 	// 送回渠道。
 	if target.private {
-		b.persistToMain(ctx, history.RoleAssistant, reply, mood, "", "", target.platform, deviceIDFor(msg), adapterName(a), turnID)
+		b.persistMainWith(ctx, mainRow(history.RoleAssistant, reply, mood, "", "", target.platform, deviceIDFor(msg), adapterName(a), turnID), notify)
 	} else {
-		b.persistIsolated(ctx, history.RoleAssistant, reply, "", "", "", sess, msg.Platform, "", adapterName(a), turnID)
+		b.persistIsolatedWith(ctx, isolatedRow(history.RoleAssistant, reply, "", "", "", sess, msg.Platform, "", adapterName(a), turnID), notify)
 	}
-	if err := b.sendReply(ctx, msg, a, reply); err != nil {
+	// 音频只在合成成功、且盘上那份副本读得回来时才挂上；读不回来就诚实退回纯文本
+	// （正文照发，WARN 已由 outboundVoiceMedia 记下）。
+	var voiceMedia *adapter.Media
+	if hasVoice {
+		if md, ok := b.outboundVoiceMedia(msg, ref); ok {
+			voiceMedia = &md
+		}
+	}
+	if err := b.sendReplyVoice(ctx, msg, a, reply, voiceMedia); err != nil {
 		if errors.Is(err, adapter.ErrUnsupported) {
 			b.log.Debug("channel does not support outbound reply, skipped",
 				"platform", msg.Platform, "session", target.sessionID)