feat: 第二阶段核心业务模块(CRM/房务/护理/月子餐)

后端:
- 4个迁移文件新增23张业务表
- 23个Eloquent Model(含关联/类型转换/门店隔离)
- 20个Controller(含CRUD+业务操作: 合同审核/入住退房/护理异常处理等)
- 110+条API路由(crm/room/care/meal四大前缀)

前端:
- 4个API模块(crm.js/room.js/care.js/meal.js)
- 13个业务页面(线索/客户/合同/渠道/投诉/房型/房间/预定/护理档案/护理计划/护理记录/菜品/排餐)

backend/app/Models/Crm/Complaint.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Models\Crm;
+
+use App\Models\User;
+use App\Traits\BelongsToStore;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class Complaint extends Model
+{
+    use BelongsToStore;
+
+    protected $fillable = [
+        'store_id', 'customer_id', 'type', 'content', 'images',
+        'status', 'handler_id', 'handle_result', 'handle_at',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'type' => 'integer',
+            'images' => 'array',
+            'status' => 'integer',
+            'handle_at' => 'datetime',
+        ];
+    }
+
+    public function customer(): BelongsTo
+    {
+        return $this->belongsTo(Customer::class);
+    }
+
+    public function handler(): BelongsTo
+    {
+        return $this->belongsTo(User::class, 'handler_id');
+    }
+}