fix(customer): lưu và trả địa chỉ khách hàng

Bảng customers chỉ có cột address nên address_1/address_2 từ form admin bị bỏ khi validate.
Thêm cột address_2, fillable, rule validate và trả đủ field địa chỉ trong CustomerResource.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

database/migrations/2026_10_27_000001_add_address_2_to_customers_table.php

@@ -0,0 +1,24 @@
+<?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('customers', function (Blueprint $table) {
+            $table->string('address', 255)->nullable()->change();
+            $table->string('address_2', 255)->nullable()->after('address');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::table('customers', function (Blueprint $table) {
+            $table->dropColumn('address_2');
+            $table->string('address', 100)->nullable()->change();
+        });
+    }
+};