feat(call): integrate LiveKit for voice and video calling

Replace the manual WebRTC signaling implementation with LiveKit SFU. This includes:
- Adding LiveKit service, handler, and configuration.
- Updating Docker Compose to include LiveKit server, Redis, and PostgreSQL.
- Refactoring `CallService` and `WSHandler` to support LiveKit room readiness instead of raw SDP/ICE relaying.
- Adding new API endpoints for LiveKit token generation and webhooks.
- Removing deprecated WebRTC configuration and manual signaling DTOs.

internal/service/call_service.go

@@ -59,8 +59,6 @@ type ActiveCall struct {
 	Duration       int64 // 通话时长（秒）
 	// 参与者状态
 	Participants map[string]*ActiveParticipant
-	// ICE Servers
-	ICEServers []config.ICEServerConfig
 }
 
 // ActiveParticipant 内存中的活跃参与者
@@ -77,10 +75,10 @@ type CallService interface {
 	Reject(ctx context.Context, callID, userID string) error
 	Busy(ctx context.Context, callID, userID string) error
 	End(ctx context.Context, callID, userID string, reason string) (*ActiveCall, error)
-	RelaySignal(ctx context.Context, callID, fromUserID string, signalType string, payload json.RawMessage) error
 	SetMuted(ctx context.Context, callID, userID string, muted bool) error
+	Ready(ctx context.Context, callID, userID string) error
+	GetActiveCall(ctx context.Context, callID string) *ActiveCall
 	GetCallHistory(ctx context.Context, userID string, page, pageSize int) ([]model.CallSession, int64, error)
-	GetICEServers() []config.ICEServerConfig
 	StartCleanupTicker()
 }
 
@@ -217,8 +215,7 @@ func (s *callService) redisGetCall(callID string) *ActiveCall {
 		CallType:       model.CallType(data.CallType),
 		Status:         model.CallStatus(data.Status),
 		MediaType:      data.MediaType,
-		ICEServers:     s.config.WebRTC.ICEServers,
-		Participants: map[string]*ActiveParticipant{
+				Participants: map[string]*ActiveParticipant{
 			data.CallerID: {UserID: data.CallerID, Status: model.ParticipantStatusJoined},
 			data.CalleeID: {UserID: data.CalleeID, Status: model.ParticipantStatusInvited},
 		},
@@ -390,8 +387,7 @@ func (s *callService) Invite(ctx context.Context, callerID, calleeID, conversati
 			callerID: {UserID: callerID, Status: model.ParticipantStatusJoined, JoinedAt: &now},
 			calleeID: {UserID: calleeID, Status: model.ParticipantStatusInvited},
 		},
-		ICEServers: s.config.WebRTC.ICEServers,
-	}
+			}
 
 	// 存储到内存
 	s.storeActiveCall(call)
@@ -411,8 +407,7 @@ func (s *callService) Invite(ctx context.Context, callerID, calleeID, conversati
 		"media_type":      mediaType,
 		"created_at":      now.UnixMilli(),
 		"lifetime":        CallLifetimeMs,
-		"ice_servers":     s.config.WebRTC.ICEServers,
-	}
+			}
 
 	online := s.hub.PublishToUserOnline(calleeID, "call_incoming", payload)
 
@@ -473,8 +468,7 @@ func (s *callService) Accept(ctx context.Context, callID, userID string) (*Activ
 	s.hub.PublishToUserOnline(call.CallerID, "call_accepted", map[string]any{
 		"call_id":     callID,
 		"started_at":  now.UnixMilli(),
-		"ice_servers": s.config.WebRTC.ICEServers,
-	})
+			})
 
 	// 通知被叫方其他设备
 	s.hub.PublishToUserOnline(userID, "call_answered_elsewhere", map[string]any{
@@ -626,35 +620,6 @@ func (s *callService) End(ctx context.Context, callID, userID string, reason str
 	return call, nil
 }
 
-func (s *callService) RelaySignal(ctx context.Context, callID, fromUserID string, signalType string, payload json.RawMessage) error {
-	call := s.getActiveCall(callID)
-	if call == nil {
-		return apperrors.ErrCallNotFound
-	}
-
-	s.mu.RLock()
-	if call.Status != model.CallStatusCalling && call.Status != model.CallStatusConnected {
-		s.mu.RUnlock()
-		return apperrors.ErrCallNotActive
-	}
-	if !isParticipant(call, fromUserID) {
-		s.mu.RUnlock()
-		return apperrors.ErrNotCallParticipant
-	}
-	s.mu.RUnlock()
-
-	for pUserID := range call.Participants {
-		if pUserID != fromUserID {
-			s.hub.PublishToUserOnlineReliable(pUserID, signalType, map[string]any{
-				"call_id": callID,
-				"from_id": fromUserID,
-				"payload": json.RawMessage(payload),
-			})
-		}
-	}
-	return nil
-}
-
 func (s *callService) SetMuted(ctx context.Context, callID, userID string, muted bool) error {
 	call := s.getActiveCall(callID)
 	if call == nil {
@@ -684,13 +649,41 @@ func (s *callService) SetMuted(ctx context.Context, callID, userID string, muted
 	return nil
 }
 
+// GetActiveCall 获取活跃通话（公开方法，供 LiveKit handler 调用）
+func (s *callService) GetActiveCall(ctx context.Context, callID string) *ActiveCall {
+	return s.getActiveCall(callID)
+}
+
+// Ready 标记参与者已加入 LiveKit 房间
+func (s *callService) Ready(ctx context.Context, callID, userID string) error {
+	call := s.getActiveCall(callID)
+	if call == nil {
+		return apperrors.ErrCallNotFound
+	}
+
+	s.mu.RLock()
+	if !isParticipant(call, userID) {
+		s.mu.RUnlock()
+		return apperrors.ErrNotCallParticipant
+	}
+	s.mu.RUnlock()
+
+	// 通知其他参与者该用户已就绪
+	for pUserID := range call.Participants {
+		if pUserID != userID {
+			s.hub.PublishToUserOnline(pUserID, "call_ready", map[string]any{
+				"call_id": callID,
+				"user_id": userID,
+			})
+		}
+	}
+	return nil
+}
+
 func (s *callService) GetCallHistory(ctx context.Context, userID string, page, pageSize int) ([]model.CallSession, int64, error) {
 	return s.callRepo.GetCallHistory(userID, page, pageSize)
 }
 
-func (s *callService) GetICEServers() []config.ICEServerConfig {
-	return s.config.WebRTC.ICEServers
-}
 
 // saveCallHistory 保存通话历史到数据库
 func (s *callService) saveCallHistory(call *ActiveCall, status model.CallStatus, duration int64) {