feat(webstatement): tambahkan kolom dealer_desk pada model dan tabel tellers

- Menambahkan atribut baru `dealer_desk` pada properti `$fillable` di model `Teller` untuk memungkinkan atribut ini diisi secara massal.
- Membuat migration baru `2025_05_29_024729_add_dealer_desk_to_tellers_table` untuk penambahan kolom `dealer_desk` ke dalam tabel `tellers`.
  - Kolom `dealer_desk` bertipe string dan dapat bernilai null.
  - Penempatan kolom dilakukan setelah kolom `last_version`.
- Menambahkan method untuk rollback migration yang menghapus kolom `dealer_desk` dari tabel `tellers`.

Signed-off-by: Daeng Deni Mardaeni <ddeni05@gmail.com>

app/Models/Teller.php

@@ -112,6 +112,7 @@
             'amount_fcy_2',
             'rate_2',
             'customer_1',
-            'last_version'
+            'last_version',
+            'dealer_desk'
         ];
     }

database/migrations/2025_05_29_024729_add_dealer_desk_to_tellers_table.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('tellers', function (Blueprint $table) {
+                $table->string('dealer_desk')->nullable()->after('last_version');
+            });
+        }
+
+        /**
+         * Reverse the migrations.
+         */
+        public function down(): void
+        {
+            Schema::table('tellers', function (Blueprint $table) {
+                $table->dropColumn('dealer_desk');
+            });
+        }
+    };