Add invoice SMS notifications and customer intake kiosk

Invoice SMS:
- Send Invoice modal now prompts Email/SMS/Both based on customer contact data
- New /invoice/{token} customer-facing view page with full line items and pay button
- PublicViewToken (permanent) added to Invoice; separate from expiring PaymentLinkToken
- InvoiceSent SMS default template added; customizable via Notification Templates settings
- {{viewUrl}} placeholder documented in template editor

Customer Intake Kiosk:
- Tablet kiosk flow: Contact → Job → Terms/Signature → Confirmation
- Remote link mode for off-site customers (lighter form, no signature)
- KioskHub (AllowAnonymous SignalR) for staff-to-tablet push without login
- Staff activates tablet via cookie; sends remote link manually
- Submitted sessions create Customer + Job automatically; fires in-app notification

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

src/PowderCoating.Core/Entities/Company.cs

@@ -123,6 +123,16 @@ public class Company : BaseEntity
     public byte[]? LogoData { get; set; }  // Legacy - kept for backward compatibility
     public string? LogoContentType { get; set; }  // Legacy - kept for backward compatibility
     public string? LogoFilePath { get; set; }  // Filesystem path: /media/{CompanyId}/company-logo.{ext}
+
+    // Kiosk
+    /// <summary>
+    /// Random token written to a long-lived HttpOnly cookie on the front-desk tablet when the
+    /// owner activates the kiosk. Kiosk routes validate this token against the cookie so the
+    /// tablet can serve the intake form without requiring a logged-in user.
+    /// Null = kiosk not activated. Regenerate to revoke the current device.
+    /// </summary>
+    public string? KioskActivationToken { get; set; }
+
     // Navigation Properties
     public virtual ICollection<ApplicationUser> Users { get; set; } = new List<ApplicationUser>();
     public virtual ICollection<Customer> Customers { get; set; } = new List<Customer>();