refactor(inventory): 重構倉庫管理邏輯，移除 is_sellable 欄位並改由類型判定可用庫存

database/migrations/tenant/2026_01_27_102239_remove_is_sellable_from_warehouses.php

@@ -0,0 +1,28 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::table('warehouses', function (Blueprint $table) {
+            $table->dropColumn('is_sellable');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('warehouses', function (Blueprint $table) {
+            $table->boolean('is_sellable')->default(true)->after('description')->comment('是否可銷售');
+        });
+    }
+};