Rewrite the showcase's Data section without Tailwind

Plan step 38: text.css already has the three classes this section
needed (md-text-end, md-tabular, md-visually-hidden), so only the
table's own scroll wrapper and the pagination list move — the wrapper
to a data-md-showcase-table-scroll hook, the two paginators onto
<x-stack>.

Every #data id and data-md-list-row/aria-selected selector the
Chromium DataTest reads is unchanged.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

resources/css/showcase.css

@@ -440,6 +440,12 @@
     [data-md-showcase-search-bar-title] {
         flex: 1 1 auto;
     }
+
+    /* Data: the table's own horizontal scroll stays the caller's, as table.css's header says. */
+    [data-md-showcase-table-scroll] {
+        width: 100%;
+        overflow-x: auto;
+    }
 }
 
 /* A handful of call sites (<x-input>, <x-datepicker>, <x-slider>) forward only `class` and