Fix Bills detail page horizontal scrolling on mobile

Wrap Line Items and Payment History tables in table-responsive so they
scroll horizontally rather than overflowing the viewport. Expenses detail
page uses a definition list layout and was not affected.

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

src/PowderCoating.Web/Views/Bills/Details.cshtml

@@ -127,6 +127,7 @@
         <div class="card shadow-sm mb-4">
             <div class="card-header fw-semibold">Line Items</div>
             <div class="card-body p-0">
+                <div class="table-responsive">
                 <table class="table table-sm mb-0">
                     <thead class="table-light">
                         <tr>
@@ -171,6 +172,7 @@
                 </table>
                 </div>
             </div>
+        </div>
 
         <!-- Receipt attachment -->
         @if (!string.IsNullOrEmpty(Model.ReceiptFilePath))
@@ -210,6 +212,7 @@
                     </a>
                 </div>
                 <div class="card-body p-0">
+                    <div class="table-responsive">
                     <table class="table table-sm mb-0">
                         <thead class="table-light">
                             <tr>
@@ -255,6 +258,7 @@
                     </table>
                     </div>
                 </div>
+            </div>
         }
     </div>