Add unique foreign keys for EggVariable (#1196)

* Fix tests \`egg_variable\` order

* Add `EggVariable` unique foreign key for `env_variable` & `name`

database/migrations/2025_04_01_033956_egg_variable_unique_foreign_key.php

@@ -0,0 +1,30 @@
+<?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('egg_variables', function (Blueprint $table) {
+            $table->unique(['egg_id', 'env_variable']);
+            $table->unique(['egg_id', 'name']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::table('egg_variables', function (Blueprint $table) {
+            $table->dropUnique(['egg_id', 'env_variable']);
+            $table->dropUnique(['egg_id', 'name']);
+        });
+    }
+};