feat(call): enhance call handling with user connection events and active call management

- Updated CallService to handle user connection and disconnection events, allowing for automatic management of active calls based on user status.
- Introduced methods to retrieve active calls for users and send pending call invites when users reconnect.
- Modified the Invite method to return the callee's online status, improving user experience during call invitations.
- Enhanced WSHandler to support connection and disconnection event handlers, ensuring accurate call state management.

internal/handler/ws_handler.go

@@ -467,18 +467,13 @@ func (h *WSHandler) handleCallInvite(ctx context.Context, client *ws.Client, pay
 		mediaType = "voice"
 	}
 
-	call, err := h.callService.Invite(ctx, client.UserID, req.CalleeID, req.ConversationID, mediaType)
+	call, _, err := h.callService.Invite(ctx, client.UserID, req.CalleeID, req.ConversationID, mediaType)
 	if err != nil {
 		zap.L().Warn("Failed to invite call",
 			zap.String("caller_id", client.UserID),
 			zap.String("callee_id", req.CalleeID),
 			zap.Error(err),
 		)
-		// === 区分不同错误类型 ===
-		if errors.Is(err, service.ErrCalleeOffline) {
-			h.wsHub.SendError(client, "callee_offline", "对方当前离线，无法拨打")
-			return
-		}
 		if errors.Is(err, service.ErrCallInProgress) {
 			h.wsHub.SendError(client, "call_in_progress", err.Error())
 			return
@@ -487,6 +482,7 @@ func (h *WSHandler) handleCallInvite(ctx context.Context, client *ws.Client, pay
 		return
 	}
 
+	// 返回给呼叫方的响应
 	resp := ws.ResponseMessage{
 		EventID: h.wsHub.NextID(),
 		Type:    "call_invited",
@@ -495,6 +491,7 @@ func (h *WSHandler) handleCallInvite(ctx context.Context, client *ws.Client, pay
 			"call_id":         call.ID,
 			"conversation_id": req.ConversationID,
 			"callee_id":       req.CalleeID,
+			"lifetime":        service.CallLifetimeMs,
 		},
 	}
 	data, _ := json.Marshal(resp)