Add SMS Agreements admin page and update help docs

- Add /SmsAgreements SuperAdmin page listing per-company SMS terms acceptance
  status, with stats cards, filter/search, and a full acceptance history modal
  (terms version, accepted by, timestamp, IP, user agent)
- Add SMS Agreements nav link under Tenants & Billing in the platform sidebar
- Update HelpKnowledgeBase and Help docs (Quotes, Settings) to document
  quote approval via SMS and the reuse of existing approval tokens

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

src/PowderCoating.Web/Controllers/SmsAgreementsController.cs

@@ -0,0 +1,99 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using PowderCoating.Core.Interfaces;
+using PowderCoating.Shared.Constants;
+
+namespace PowderCoating.Web.Controllers;
+
+/// <summary>
+/// SuperAdmin view of per-company SMS terms agreement history.
+/// Shows which companies have accepted the current SMS terms, who accepted them,
+/// and the full acceptance log for each company.
+/// </summary>
+[Authorize(Policy = AppConstants.Policies.SuperAdminOnly)]
+public class SmsAgreementsController : Controller
+{
+    private readonly IUnitOfWork _unitOfWork;
+    private readonly ILogger<SmsAgreementsController> _logger;
+
+    public SmsAgreementsController(IUnitOfWork unitOfWork, ILogger<SmsAgreementsController> logger)
+    {
+        _unitOfWork = unitOfWork;
+        _logger = logger;
+    }
+
+    /// <summary>
+    /// Lists every company with its current SMS agreement status and full acceptance history.
+    /// Uses IgnoreQueryFilters on both queries so deleted/inactive companies and all historical
+    /// agreement records are included in the audit view.
+    /// </summary>
+    public async Task<IActionResult> Index(string? search = null, string? filter = null)
+    {
+        var companies = await _unitOfWork.Companies.GetAllAsync(ignoreQueryFilters: true);
+        var allAgreements = await _unitOfWork.CompanySmsAgreements.GetAllAsync(ignoreQueryFilters: true);
+
+        var agreementsByCompany = allAgreements
+            .GroupBy(a => a.CompanyId)
+            .ToDictionary(g => g.Key, g => g.OrderByDescending(a => a.AgreedAt).ToList());
+
+        var rows = companies
+            .OrderBy(c => c.CompanyName)
+            .Select(c =>
+            {
+                var agreements = agreementsByCompany.TryGetValue(c.Id, out var list) ? list : [];
+                var current = agreements.FirstOrDefault(a => a.TermsVersion == AppConstants.SmsTermsVersion);
+                return new CompanySmsRow
+                {
+                    CompanyId = c.Id,
+                    CompanyName = c.CompanyName ?? "(unnamed)",
+                    SmsEnabled = c.SmsEnabled,
+                    SmsDisabledByAdmin = c.SmsDisabledByAdmin,
+                    CurrentAgreement = current,
+                    LatestAgreement = agreements.FirstOrDefault(),
+                    AllAgreements = agreements,
+                    IsDeleted = c.IsDeleted
+                };
+            })
+            .ToList();
+
+        // Filter
+        rows = filter switch
+        {
+            "accepted" => rows.Where(r => r.CurrentAgreement != null).ToList(),
+            "pending"  => rows.Where(r => r.CurrentAgreement == null).ToList(),
+            "enabled"  => rows.Where(r => r.SmsEnabled).ToList(),
+            "disabled" => rows.Where(r => r.SmsDisabledByAdmin).ToList(),
+            _          => rows
+        };
+
+        if (!string.IsNullOrWhiteSpace(search))
+            rows = rows.Where(r => r.CompanyName.Contains(search, StringComparison.OrdinalIgnoreCase)).ToList();
+
+        ViewBag.Search = search;
+        ViewBag.Filter = filter ?? "all";
+        ViewBag.CurrentTermsVersion = AppConstants.SmsTermsVersion;
+
+        // Stats (pre-filter totals)
+        var all = companies.ToList();
+        ViewBag.TotalCompanies    = all.Count(c => !c.IsDeleted);
+        ViewBag.AcceptedCount     = agreementsByCompany.Count(kvp =>
+            kvp.Value.Any(a => a.TermsVersion == AppConstants.SmsTermsVersion) &&
+            !all.FirstOrDefault(c => c.Id == kvp.Key)?.IsDeleted == true);
+        ViewBag.SmsEnabledCount   = all.Count(c => !c.IsDeleted && c.SmsEnabled);
+
+        return View(rows);
+    }
+}
+
+/// <summary>View model for one company row on the SMS agreements page.</summary>
+public class CompanySmsRow
+{
+    public int CompanyId { get; set; }
+    public string CompanyName { get; set; } = string.Empty;
+    public bool SmsEnabled { get; set; }
+    public bool SmsDisabledByAdmin { get; set; }
+    public bool IsDeleted { get; set; }
+    public PowderCoating.Core.Entities.CompanySmsAgreement? CurrentAgreement { get; set; }
+    public PowderCoating.Core.Entities.CompanySmsAgreement? LatestAgreement { get; set; }
+    public List<PowderCoating.Core.Entities.CompanySmsAgreement> AllAgreements { get; set; } = [];
+}