feat: add mail_accounts migration and MailAccount model

database/migrations/2026_05_26_000001_create_mail_accounts_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
+{
+    public function up(): void
+    {
+        Schema::create('mail_accounts', function (Blueprint $table) {
+            $table->id();
+            $table->string('name', 100)->unique();
+            $table->string('label', 150);
+            $table->enum('type', ['azure', 'smtp']);
+            $table->string('from_address', 255);
+            $table->string('from_name', 150)->nullable();
+            $table->text('config');
+            $table->boolean('enabled')->default(true);
+            $table->timestamps();
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('mail_accounts');
+    }
+};