wire postgres session repo, migrations, seed, and dev serve

backend/database/migrations/2026_05_17_000002_create_sessions_table.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Database\Migrations;
+
+use App\Database\Migration;
+use Illuminate\Database\Capsule\Manager as Capsule;
+
+class CreateSessionsTable extends Migration
+{
+    public function up(): void
+    {
+        Capsule::schema()->create('sessions', function ($table) {
+            $table->string('token')->primary();
+            $table->integer('user_id')->unsigned();
+            $table->foreign('user_id')
+                ->references('id')
+                ->on('users')
+                ->cascadeOnDelete();
+            $table->dateTime('expires_at');
+            $table->dateTime('created_at');
+        });
+    }
+
+    public function down(): void
+    {
+        Capsule::schema()->dropIfExists('sessions');
+    }
+}
+
+return CreateSessionsTable::class;