fix(diet): DietMealConfigService 参数空值校验防 NPE（date_type/meal_type/participant_member_ids 必填）

cfc-backend/src/main/java/com/etotem/cfc/service/DietMealConfigService.java

@@ -43,10 +43,22 @@ public class DietMealConfigService {
     }
 
     public void saveConfig(Long familyId, Map<String, Object> request) {
-        String dateType = request.get("date_type").toString();
-        String mealType = request.get("meal_type").toString();
-        String participantMemberIds = request.get("participant_member_ids").toString();
-        String notes = request.containsKey("notes") ? request.get("notes").toString() : null;
+        String dateType = request.get("date_type") != null ? request.get("date_type").toString() : null;
+        String mealType = request.get("meal_type") != null ? request.get("meal_type").toString() : null;
+        String participantMemberIds = request.get("participant_member_ids") != null
+                ? request.get("participant_member_ids").toString() : null;
+        String notes = request.containsKey("notes") && request.get("notes") != null
+                ? request.get("notes").toString() : null;
+
+        if (dateType == null || dateType.isEmpty()) {
+            throw new IllegalArgumentException("缺少必填参数: date_type");
+        }
+        if (mealType == null || mealType.isEmpty()) {
+            throw new IllegalArgumentException("缺少必填参数: meal_type");
+        }
+        if (participantMemberIds == null) {
+            throw new IllegalArgumentException("缺少必填参数: participant_member_ids");
+        }
 
         LambdaQueryWrapper<MealConfig> wrapper = new LambdaQueryWrapper<>();
         wrapper.eq(MealConfig::getFamilyId, familyId)