Button consistency sweep + mobile responsiveness patches

- Standardize modal dismiss/cancel buttons to btn-outline-secondary across 70+ views
- Remove btn-sm from page-level Create and Back buttons (Index + Detail pages)
- Fix Edit buttons on Details pages: btn-secondary -> btn-warning
- Fix form Cancel/Back links: btn-secondary -> btn-outline-secondary
- Add 10 CSS patches to site.css for mobile/tablet responsiveness:
  top-navbar overflow prevention, page-header flex-wrap at 575px,
  table action button min-height override, notification dropdown width cap,
  tablet content padding

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

src/PowderCoating.Web/Views/Maintenance/Delete.cshtml

@@ -98,14 +98,14 @@
                 </div>
             </div>
             <div class="text-end">
-                <a asp-action="Details" asp-route-id="@Model.Id" class="btn btn-secondary">Cancel</a>
+                <a asp-action="Details" asp-route-id="@Model.Id" class="btn btn-outline-secondary">Cancel</a>
             </div>
         }
         else
         {
             <!-- Simple single delete -->
             <div class="d-flex gap-2 justify-content-end">
-                <a asp-action="Details" asp-route-id="@Model.Id" class="btn btn-secondary">Cancel</a>
+                <a asp-action="Details" asp-route-id="@Model.Id" class="btn btn-outline-secondary">Cancel</a>
                 <form asp-action="Delete" method="post">
                     @Html.AntiForgeryToken()
                     <input type="hidden" name="id" value="@Model.Id" />