feat: add save feature

database/migrations/2026_05_22_200854_create_saved_items_table.php

@@ -0,0 +1,31 @@
+<?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::create('saved_items', function (Blueprint $table) {
+           $table->id();
+            $table->foreignId('user_id')->constrained()->onDelete('cascade');
+            $table->morphs('saveable'); // saveable_id + saveable_type
+            $table->timestamps();
+            
+            $table->unique(['user_id', 'saveable_id', 'saveable_type']);
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('saved_items');
+    }
+};