feat: 第三阶段业务模块(服务产康/月嫂/进销存)

- 新增3个migration(15张表): service/nanny/inventory
- 新增15个Model + 13个Controller
- 新增55条API路由(总计212条)
- 新增3个前端API模块 + 11个管理页面
- vite build验证通过

backend/app/Models/Service/ServiceOrder.php

@@ -0,0 +1,17 @@
+<?php
+namespace App\Models\Service;
+use App\Models\Crm\Customer;
+use App\Models\User;
+use App\Traits\BelongsToStore;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+class ServiceOrder extends Model
+{
+    use BelongsToStore;
+    protected $fillable = ['store_id','customer_id','order_no','type','items','total_amount','discount_amount','actual_amount','status','pay_method','paid_at','created_by'];
+    protected function casts(): array { return ['type'=>'integer','items'=>'array','total_amount'=>'decimal:2','discount_amount'=>'decimal:2','actual_amount'=>'decimal:2','status'=>'integer','pay_method'=>'integer','paid_at'=>'datetime']; }
+    public function customer(): BelongsTo { return $this->belongsTo(Customer::class); }
+    public function creator(): BelongsTo { return $this->belongsTo(User::class, 'created_by'); }
+    public function executions(): HasMany { return $this->hasMany(ServiceExecution::class); }
+}