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/CompanySmsAgreement.cs

@@ -0,0 +1,33 @@
+namespace PowderCoating.Core.Entities;
+
+/// <summary>
+/// Immutable audit record of a company admin accepting the SMS terms of service.
+/// One record is written each time a user accepts (including re-accepts after a terms update).
+/// The most recent record whose <see cref="TermsVersion"/> matches
+/// <c>AppConstants.SmsTermsVersion</c> is the authoritative acceptance for that company.
+/// Never soft-deleted — this is a legal audit trail.
+/// </summary>
+public class CompanySmsAgreement : BaseEntity
+{
+    /// <summary>The Identity user ID of the admin who clicked "I Agree".</summary>
+    public string AgreedByUserId { get; set; } = string.Empty;
+
+    /// <summary>Display name snapshot of the user at the time of agreement (for audit readability after user changes).</summary>
+    public string AgreedByUserName { get; set; } = string.Empty;
+
+    /// <summary>UTC timestamp of acceptance.</summary>
+    public DateTime AgreedAt { get; set; }
+
+    /// <summary>Client IP address at the time of acceptance. Stored for legal/fraud purposes.</summary>
+    public string? IpAddress { get; set; }
+
+    /// <summary>HTTP User-Agent header at the time of acceptance.</summary>
+    public string? UserAgent { get; set; }
+
+    /// <summary>
+    /// The version of the SMS terms that was accepted (matches <c>AppConstants.SmsTermsVersion</c>
+    /// at the moment of acceptance). When the platform bumps this version, existing records become
+    /// stale and the company must re-accept.
+    /// </summary>
+    public string TermsVersion { get; set; } = string.Empty;
+}