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

composer.json

@@ -5,18 +5,21 @@
     "license": "MIT",
     "type": "project",
     "require": {
-        "laravel/framework": "5.1.*",
+        "php": ">=7.0.0",
+        "laravel/framework": "5.5.*",
         "webpatser/laravel-uuid": "^2.0",
         "netshell/paypal": "dev-master",
-        "guzzlehttp/guzzle": "~6.0",
+        "guzzlehttp/guzzle": "^6.3",
         "google/recaptcha": "~1.1",
-        "spatie/laravel-analytics": "^1.4",
+        "spatie/laravel-analytics": "^2.0",
         "league/flysystem-sftp": "^1.0",
         "aws/aws-sdk-php": "~3.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~4.0",
-        "phpspec/phpspec": "~2.1"
+        "filp/whoops": "~2.0",
+        "fzaninotto/faker": "~1.4",
+        "mockery/mockery": "~1.0",
+        "phpunit/phpunit": "~6.0"
     },
 
     "autoload": {
@@ -50,6 +53,9 @@
         ]
     },
     "config": {
-        "preferred-install": "dist"
+        "preferred-install": "dist",
+        "allow-plugins": {
+            "kylekatarnls/update-helper": true
+        }
     }
 }