feat: shop customer accounts (register/login + order history)

Schema:
- shop_customers (company_id, name, phone unique-per-tenant, email, password,
  client_id auto-linked, last_login_at)
- online_orders.shop_customer_id nullable FK

Auth:
- New 'shop' guard (session driver, shop_customers provider) in config/auth.php
- ShopCustomer Authenticatable with hashed password cast and BelongsToTenant
  global scope — login attempts naturally scoped to current tenant subdomain

Flow:
- ShopAuthController: register / login / logout / account
- Register auto-links to existing Client by phone match
- /shop/account: order history (only the logged customer's orders) + profile
- Checkout prefills name/phone/email from logged customer + sets
  shop_customer_id (and client_id from auto-link) on the placed order
- Layout nav switches between Login/Register and "👤 Name + Ieșire"

Tests (8 new):
- register creates customer + auto-login
- register auto-links existing Client by phone
- duplicate phone rejected
- login validates credentials
- /account requires auth (redirects to /shop/login)
- /account lists only the logged customer's orders
- checkout attaches shop_customer_id
- customers tenant-isolated

Full suite: 117 passed.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

config/auth.php

@@ -22,6 +22,12 @@ return [
             'driver' => 'session',
             'provider' => 'super_admins',
         ],
+
+        // Public storefront customer auth (per-tenant).
+        'shop' => [
+            'driver' => 'session',
+            'provider' => 'shop_customers',
+        ],
     ],
 
     'providers' => [
@@ -33,6 +39,10 @@ return [
             'driver' => 'eloquent',
             'model' => SuperAdmin::class,
         ],
+        'shop_customers' => [
+            'driver' => 'eloquent',
+            'model' => \App\Models\Tenant\ShopCustomer::class,
+        ],
     ],
 
     'passwords' => [