Add SMS gating, TCPA terms agreement, and compose-before-send modal

- Three-tier SMS gate: platform kill-switch → admin force-disable → plan AllowSms → company opt-in
- CompanySmsAgreement entity records admin acceptance of TCPA terms with IP, user agent, and terms version
- SMS terms of service modal on Company Settings with versioned re-agreement (AppConstants.SmsTermsVersion)
- Dev redirect: non-production SMS routed to Twilio:DevRedirectPhone to protect real customer numbers
- Removed redundant Ready for Pickup SMS (Job Completed covers it)
- Role-based compose modal on job completion: Admin/Manager reviews and edits before send; ShopFloor auto-sends
- Send SMS button on job details for ad-hoc messages (Admin/Manager only)
- SendJobSmsAsync auto-appends STOP opt-out language if missing
- Migrations: AddSmsGating, AddCompanySmsAgreement

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

src/PowderCoating.Core/Entities/SubscriptionPlanConfig.cs

@@ -49,6 +49,9 @@ public class SubscriptionPlanConfig : BaseEntity
     /// <summary>When true, companies on this plan can run the AI Catalog Price Check (Enterprise only).</summary>
     public bool AllowAiCatalogPriceCheck { get; set; } = false;
 
+    /// <summary>When true, companies on this plan can send SMS notifications to customers (subject to platform kill-switch and per-company opt-in).</summary>
+    public bool AllowSms { get; set; } = false;
+
     public bool IsActive { get; set; } = true;
     public int SortOrder { get; set; }
 }