Fix Reset Demo Company: full wipe mode + missing removal categories

Root cause: fingerprint-based removal failed on databases seeded with
older code (different emails/SKUs); plus Vendors, Named Ovens, and
Appointments had no removal path at all.

- Add ForceRemoveAll flag to RemoveSeedDataOptions: when true, all
  removal blocks delete by CompanyId instead of fingerprint matching
- Customers block: ForceRemoveAll deletes all company customers
- Workers block: ForceRemoveAll deletes all users with CompanyRole=Worker
- New Vendors block (triggered by options.Vendors || ForceRemoveAll)
- New NamedOvens (OvenCost) block (triggered by options.NamedOvens || ForceRemoveAll)
- New Appointments block (triggered by options.Appointments || ForceRemoveAll)
- ResetDemoCompany: set ForceRemoveAll=true and enable all new flags so
  every re-seedable table is wiped clean before re-seeding

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

src/PowderCoating.Web/Controllers/SeedDataController.cs

@@ -125,7 +125,8 @@ public class SeedDataController : Controller
                 return RedirectToAction(nameof(Index));
             }
 
-            // Remove all seed data categories
+            // Full wipe — ForceRemoveAll bypasses fingerprint matching so stale seed data from
+            // previous code versions (different emails, renamed SKUs, etc.) is always cleared.
             var removeOptions = new RemoveSeedDataOptions
             {
                 Customers      = true,
@@ -137,6 +138,10 @@ public class SeedDataController : Controller
                 Bills          = true,
                 Expenses       = true,
                 Workers        = true,
+                Vendors        = true,
+                NamedOvens     = true,
+                Appointments   = true,
+                ForceRemoveAll = true,
             };
 
             var removeResult = await _seedDataService.RemoveSeedDataAsync(demo.Id, removeOptions);