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>

app/Models/Tenant/OnlineOrder.php

@@ -29,7 +29,7 @@ class OnlineOrder extends Model
     ];
 
     protected $fillable = [
-        'company_id', 'number', 'tracking_token', 'client_id',
+        'company_id', 'number', 'tracking_token', 'client_id', 'shop_customer_id',
         'customer_name', 'customer_phone', 'customer_email',
         'delivery_method', 'address', 'status',
         'subtotal', 'delivery_fee', 'total', 'notes',
@@ -51,6 +51,11 @@ class OnlineOrder extends Model
         return $this->belongsTo(Client::class);
     }
 
+    public function shopCustomer(): BelongsTo
+    {
+        return $this->belongsTo(ShopCustomer::class);
+    }
+
     public function trackingUrl(): string
     {
         return url('/shop/order/' . $this->tracking_token);