Hide churned trial accounts from company/health screens by default

- Companies list and Company Health now hide Expired/Canceled accounts
  whose subscription ended 14+ days ago; show/hide toggle via banner
- KPI cards on Company Health exclude churned tenants when hidden
- showChurned param threads through sort, pagination, search, and filter forms
- Powder catalog: fix missing UnitPrice on user-contributed entries;
  add back-sync to fill catalog gaps on existing matches; wire
  AiAugmentFromUrl and manual inventory Create into catalog contribute path

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

src/PowderCoating.Web/Controllers/CompaniesController.cs

@@ -66,15 +66,16 @@ public class CompaniesController : Controller
         string sortColumn = "CompanyName",
         string sortDirection = "asc",
         int pageNumber = 1,
-        int pageSize = 25)
+        int pageSize = 25,
+        bool showChurned = false)
     {
         try
         {
             pageNumber = Math.Max(1, pageNumber);
             pageSize = pageSize is 10 or 25 or 50 or 100 ? pageSize : 25;
 
-            var (companies, totalCount) = await _companyList.GetPagedAsync(
-                searchTerm, sortColumn, sortDirection, pageNumber, pageSize);
+            var (companies, totalCount, churnedCount) = await _companyList.GetPagedAsync(
+                searchTerm, sortColumn, sortDirection, pageNumber, pageSize, hideChurned: !showChurned);
 
             var companyDtos = _mapper.Map<List<CompanyListDto>>(companies);
 
@@ -128,6 +129,8 @@ public class CompaniesController : Controller
             ViewBag.PageSize = pageSize;
             ViewBag.TotalPages = (int)Math.Ceiling(totalCount / (double)pageSize);
             ViewBag.ImpersonatingCompanyId = HttpContext.Session.GetInt32("ImpersonatingCompanyId");
+            ViewBag.ShowChurned = showChurned;
+            ViewBag.ChurnedCount = churnedCount;
 
             return View(companyDtos);
         }