Add plan upgrade/downgrade, order management, impersonation, and contact form

- Plan upgrade/downgrade flow: UpgradeController with price difference
  calculations, Upgrade.vue with feature comparison and confirmation dialog
- Admin order management: Order model/migration/factory, OrderController
  with process/complete/cancel/notes, Index and Show pages with filters
- Admin impersonation: start/stop endpoints, session-based tracking,
  impersonation banner in AccountLayout, audit logging
- Contact form: ContactRequest validation, ContactController with email,
  marketing route for form submission
- FlashMessages now supports info alerts
- Inertia shared data includes impersonation state
- 114 tests passing (623 assertions)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

website/app/Models/Order.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Factories\HasFactory;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class Order extends Model
+{
+    use HasFactory;
+
+    protected $fillable = [
+        'user_id',
+        'plan_id',
+        'invoice_id',
+        'service_id',
+        'order_number',
+        'status',
+        'total',
+        'currency',
+        'payment_gateway',
+        'configuration',
+        'admin_notes',
+        'completed_at',
+        'cancelled_at',
+    ];
+
+    protected function casts(): array
+    {
+        return [
+            'total' => 'decimal:2',
+            'configuration' => 'json',
+            'completed_at' => 'datetime',
+            'cancelled_at' => 'datetime',
+        ];
+    }
+
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function plan(): BelongsTo
+    {
+        return $this->belongsTo(Plan::class);
+    }
+
+    public function invoice(): BelongsTo
+    {
+        return $this->belongsTo(Invoice::class);
+    }
+
+    public function service(): BelongsTo
+    {
+        return $this->belongsTo(Service::class);
+    }
+}

website/app/Models/Plan.php

@@ -38,6 +38,11 @@ class Plan extends Model
         ];
     }
 
+    public function orders(): HasMany
+    {
+        return $this->hasMany(Order::class);
+    }
+
     public function services(): HasMany
     {
         return $this->hasMany(Service::class);

website/app/Models/User.php

@@ -79,6 +79,11 @@ class User extends Authenticatable implements MustVerifyEmail
         return $this->hasMany(SupportTicket::class);
     }
 
+    public function orders(): HasMany
+    {
+        return $this->hasMany(Order::class);
+    }
+
     public function couponRedemptions(): HasMany
     {
         return $this->hasMany(CouponRedemption::class);