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/Inventory/StockMovement.php

@@ -0,0 +1,14 @@
+<?php
+namespace App\Models\Inventory;
+use App\Models\User;
+use App\Traits\BelongsToStore;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+class StockMovement extends Model
+{
+    use BelongsToStore;
+    protected $fillable = ['store_id','warehouse_id','movement_no','type','direction','items','related_order','status','operator_id','remark'];
+    protected function casts(): array { return ['type'=>'integer','direction'=>'integer','items'=>'array','status'=>'integer']; }
+    public function warehouse(): BelongsTo { return $this->belongsTo(Warehouse::class); }
+    public function operator(): BelongsTo { return $this->belongsTo(User::class, 'operator_id'); }
+}