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.Infrastructure/Repositories/UnitOfWork.cs

@@ -36,6 +36,7 @@ public class UnitOfWork : IUnitOfWork
     private IRepository<Company>? _companies;
     private IRepository<CompanyOperatingCosts>? _companyOperatingCosts;
     private IRepository<CompanyPreferences>? _companyPreferences;
+    private IRepository<CompanySmsAgreement>? _companySmsAgreements;
 
     // AI Predictions
     private IRepository<AiItemPrediction>? _aiItemPredictions;
@@ -170,6 +171,10 @@ public class UnitOfWork : IUnitOfWork
     public IRepository<CompanyPreferences> CompanyPreferences =>
         _companyPreferences ??= new Repository<CompanyPreferences>(_context);
 
+    /// <summary>Repository for <see cref="CompanySmsAgreement"/> audit records. Tenant-filtered; never soft-deleted — legal audit trail.</summary>
+    public IRepository<CompanySmsAgreement> CompanySmsAgreements =>
+        _companySmsAgreements ??= new Repository<CompanySmsAgreement>(_context);
+
     // AI Predictions
     /// <summary>Repository for <see cref="AiItemPrediction"/> records; tenant-filtered. Shared between QuoteItem and JobItem via a single nullable FK — no duplication on quote→job conversion.</summary>
     public IRepository<AiItemPrediction> AiItemPredictions =>