feat: sync showcase with WRNexusJS 0.8.72 and @wrnexus/ui 0.8.88

- Sync app, public, scripts, test and examples from the framework's
  component-showcase: redesigned component demos, marketing blocks under
  /blocks, template and preview galleries, distinct Timeline/Section
  variants, Chat Bubble receipts, a top-placement Drawer demo, and the
  playground code panel fix (objects in array props no longer blank out).
- Standalone adaptations kept: the generator and tests read
  component-reference.json from the published @wrnexus/ui, and tests use
  the published @wrnexus/compiler and @wrnexus/syntax.
- Dependencies: every @wrnexus/* package to its latest release (ui 0.8.88,
  styles 0.8.26, core 0.8.16, cli 0.8.72, ...), happy-dom for the
  playground tests, Tailwind 4.3; bun.lock and package-lock.json refreshed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/pages/components/layout-splitter.wrn

@@ -30,7 +30,7 @@ page LayoutSplitterDetail {
       <div class="playground-workbench">
         <div class="playground-preview">
           <div class="demo-browser-chrome"><span></span><span></span><span></span><small>Live preview</small></div>
-          <div class="playground-preview-source" data-playground-preview><LayoutSplitter color='{playground_color}' size='{playground_size}' orientation='{playground_orientation}' minSize='{playground_minSize}' step='{playground_step}' label='{playground_label}' class='{playground_class}' /></div>
+          <div class="playground-preview-source" data-playground-preview><LayoutSplitter color='{playground_color}' size='{playground_size}' orientation='{playground_orientation}' minSize='{playground_minSize}' step='{playground_step}' label='{playground_label}' class='{playground_class}'><div data-slot="start"><h3>Project files</h3><p>Drag the divider to resize these panels.</p></div><div data-slot="end"><h3>Editor</h3><p>Your selected file appears here.</p></div></LayoutSplitter></div>
           <section class="playground-code" aria-label="Current component code">
             <header><span><span class="icon-[lucide--code-2] size-4" aria-hidden="true"></span>Component code</span><button type="button" data-playground-copy><span class="icon-[lucide--copy] size-4" aria-hidden="true"></span>Copy</button></header>
             <pre><code data-playground-code>&lt;LayoutSplitter
@@ -63,8 +63,8 @@ page LayoutSplitterDetail {
         <div class="demo-workbench">
           <div id="layout-splitter-demo-1" class="demo-canvas demo-canvas--1">
             <div class="demo-browser-chrome"><span></span><span></span><span></span><small>Live preview</small></div>
-
-            <div class="demo-render"><LayoutSplitter size="40" orientation="horizontal" minSize="20" step="5" label="Resize panels" class="showcase-instance showcase-instance--1" /></div>
+            
+            <div class="demo-render"><LayoutSplitter size="40" orientation="horizontal" minSize="20" step="5" label="Resize panels" class="showcase-instance showcase-instance--1"><div data-slot="start"><h3>Project files</h3><p>Drag the divider to resize these panels.</p></div><div data-slot="end"><h3>Editor</h3><p>Your selected file appears here.</p></div></LayoutSplitter></div>
           </div>
           <section class="demo-code" aria-label="Drag or arrow the divider usage">
             <header><span><span class="icon-[lucide--code-2] size-4" aria-hidden="true"></span>Component usage</span><small>.wrn</small></header>
@@ -89,8 +89,8 @@ page LayoutSplitterDetail {
         <div class="demo-workbench">
           <div id="layout-splitter-demo-2" class="demo-canvas demo-canvas--2">
             <div class="demo-browser-chrome"><span></span><span></span><span></span><small>Live preview</small></div>
-
-            <div class="demo-render"><LayoutSplitter size="60" orientation="vertical" minSize="25" step="10" label="Resize rows" class="showcase-instance showcase-instance--2" /></div>
+            
+            <div class="demo-render"><LayoutSplitter size="60" orientation="vertical" minSize="25" step="10" label="Resize rows" class="showcase-instance showcase-instance--2"><div data-slot="start"><h3>Project files</h3><p>Drag the divider to resize these panels.</p></div><div data-slot="end"><h3>Editor</h3><p>Your selected file appears here.</p></div></LayoutSplitter></div>
           </div>
           <section class="demo-code" aria-label="Stacked panes usage">
             <header><span><span class="icon-[lucide--code-2] size-4" aria-hidden="true"></span>Component usage</span><small>.wrn</small></header>