feat(call): add media type support to call invite functionality

- Updated the WSHandler to include a media type field in the call invite request, allowing differentiation between voice and video calls.
- Modified the CallService interface and implementation to accept the media type parameter during call invitations, enhancing call handling capabilities.

internal/service/call_service.go

@@ -33,7 +33,7 @@ const (
 
 // CallService 通话服务接口
 type CallService interface {
-	Invite(ctx context.Context, callerID, calleeID, conversationID string) (*model.CallSession, error)
+	Invite(ctx context.Context, callerID, calleeID, conversationID, mediaType string) (*model.CallSession, error)
 	Accept(ctx context.Context, callID, userID string) (*model.CallSession, error)
 	Reject(ctx context.Context, callID, userID string) error
 	Busy(ctx context.Context, callID, userID string) error
@@ -72,7 +72,7 @@ func NewCallService(
 	return svc
 }
 
-func (s *callService) Invite(ctx context.Context, callerID, calleeID, conversationID string) (*model.CallSession, error) {
+func (s *callService) Invite(ctx context.Context, callerID, calleeID, conversationID, mediaType string) (*model.CallSession, error) {
 	// === Telegram: 检查被叫方是否在线 ===
 	if !s.hub.HasClients(calleeID) {
 		return nil, ErrCalleeOffline
@@ -113,6 +113,7 @@ func (s *callService) Invite(ctx context.Context, callerID, calleeID, conversati
 		"conversation_id": conversationID,
 		"caller_id":       callerID,
 		"call_type":       call.CallType,
+		"media_type":      mediaType,
 		"created_at":      now.UnixMilli(),
 		"lifetime":        CallLifetimeMs,
 		"ice_servers":     s.config.WebRTC.ICEServers,