Remove accidentally committed article_number migration (was rejected)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

database/migrations/2026_09_12_230000_add_article_number_to_products.php

@@ -1,22 +0,0 @@
-<?php
-
-use Illuminate\Database\Migrations\Migration;
-use Illuminate\Database\Schema\Blueprint;
-use Illuminate\Support\Facades\Schema;
-
-return new class extends Migration
-{
-    public function up(): void
-    {
-        Schema::table('products', function (Blueprint $table) {
-            $table->string('article_number')->nullable()->unique()->after('title');
-        });
-    }
-
-    public function down(): void
-    {
-        Schema::table('products', function (Blueprint $table) {
-            $table->dropColumn('article_number');
-        });
-    }
-};