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/ShopCustomer.php

@@ -0,0 +1,42 @@
+<?php
+
+namespace App\Models\Tenant;
+
+use App\Models\Concerns\BelongsToTenant;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\SoftDeletes;
+use Illuminate\Foundation\Auth\User as Authenticatable;
+use Illuminate\Notifications\Notifiable;
+
+class ShopCustomer extends Authenticatable
+{
+    use BelongsToTenant, Notifiable, SoftDeletes;
+
+    protected $fillable = [
+        'company_id', 'client_id', 'name', 'phone', 'email', 'password', 'last_login_at',
+    ];
+
+    protected $hidden = ['password', 'remember_token'];
+
+    protected $casts = [
+        'last_login_at' => 'datetime',
+        'password' => 'hashed',
+    ];
+
+    public function client(): BelongsTo
+    {
+        return $this->belongsTo(Client::class);
+    }
+
+    public function orders(): HasMany
+    {
+        return $this->hasMany(OnlineOrder::class);
+    }
+
+    /** Auth column for Laravel's session guard. */
+    public function getAuthIdentifierName()
+    {
+        return 'id';
+    }
+}