Fix Laravel 5.5 compatibility issues - view helpers, collections, and auth routes

- Replace {{ url() }} with {{ url('/') }} in all blade templates to fix object-to-string conversion errors
- Update TeamStoreModel::selectTeamStoreGroupByCartKey() to use first() instead of get() for Laravel 5.5 Collections
- Fix TeamStoreController to access object properties directly instead of using array syntax [0]
- Update authentication routes to use Laravel 5.5 method names (showLoginForm, login, logout)
- Update login/register links from /auth/login to /login throughout views (navbar, app, auth pages)
- Verify cart, login, and register pages working with HTTP 200 status

test-key.php

@@ -0,0 +1,23 @@
+<?php
+
+require __DIR__.'/vendor/autoload.php';
+
+$app = require_once __DIR__.'/bootstrap/app.php';
+
+$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);
+
+try {
+    echo "APP_KEY from env: " . env('APP_KEY') . "\n";
+    echo "APP_CIPHER from config: " . config('app.cipher') . "\n";
+    echo "Key starts with base64: " . (strpos(env('APP_KEY'), 'base64:') === 0 ? 'YES' : 'NO') . "\n";
+    
+    $key = env('APP_KEY');
+    if (strpos($key, 'base64:') === 0) {
+        $decoded = base64_decode(substr($key, 7));
+        echo "Decoded key length: " . strlen($decoded) . " bytes\n";
+    }
+    
+} catch (Exception $e) {
+    echo "Error: " . $e->getMessage() . "\n";
+    echo "File: " . $e->getFile() . ":" . $e->getLine() . "\n";
+}