feat: Implement refresh token system for client authentication, including token creation, rotation, and revocation.

database/migrations/2026_03_16_091003_create_refresh_tokens_table.php

@@ -0,0 +1,27 @@
+<?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('refresh_tokens', function (Blueprint $table) {
+            $table->id();
+            $table->unsignedBigInteger('customer_id');
+            $table->string('token', 64)->unique(); // sha256 hex hash
+            $table->timestamp('expires_at');
+            $table->timestamps();
+
+            $table->foreign('customer_id')->references('id')->on('customers')->onDelete('cascade');
+            $table->index('customer_id');
+        });
+    }
+
+    public function down(): void
+    {
+        Schema::dropIfExists('refresh_tokens');
+    }
+};