refactor: 重构 schemas 结构，统一枚举定义

apps/lib/features/calendar/data/models/schedule_item_model.dart

@@ -2,7 +2,7 @@ import 'package:flutter/material.dart';
 
 enum ScheduleSourceType { manual, imported, agentGenerated }
 
-enum ScheduleStatus { active, completed, canceled, archived }
+enum ScheduleStatus { active, archived }
 
 class ScheduleItemModel {
   final String id;
@@ -279,9 +279,7 @@ ScheduleSourceType _sourceTypeFromApi(String? raw) {
 ScheduleStatus _statusFromApi(String? raw) {
   switch (raw) {
     case 'completed':
-      return ScheduleStatus.completed;
     case 'canceled':
-      return ScheduleStatus.canceled;
     case 'archived':
       return ScheduleStatus.archived;
     case 'active':
@@ -294,10 +292,6 @@ String _statusToApi(ScheduleStatus status) {
   switch (status) {
     case ScheduleStatus.active:
       return 'active';
-    case ScheduleStatus.completed:
-      return 'completed';
-    case ScheduleStatus.canceled:
-      return 'canceled';
     case ScheduleStatus.archived:
       return 'archived';
   }