feat(showcase/shell-dojo): update Featured selection

Replace Multimodal Attachments with Agentic Chat as the top Featured
entry (chat is a better landing demo than attachments). Append three
more entries to round out the curated set:

  Featured
    • Agentic Chat                  (was Multimodal Attachments)
    • Tool-Based Generative UI
    • Declarative Gen UI (Dynamic)
    • MCP Apps
    • Fully Open-Ended Gen UI
    • Chat Customization (CSS)      ← new
    • Headless Chat (Simple)        ← new
    • Frontend Tools                ← new (in-app actions)

All eight still appear in their real category groups below.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ataibarkai

showcase/shell-dojo/src/app/page.tsx

@@ -41,11 +41,15 @@ const demoContent = demoContentData as {
 // of the underlying feature-registry, and these demos still show up in their
 // real category groups below). Order here is the display order.
 const FEATURED_DEMO_IDS: readonly string[] = [
-  "multimodal",
+  "beautiful-chat",
+  "agentic-chat",
+  "chat-customization-css",
+  "headless-simple",
   "gen-ui-tool-based",
   "declarative-gen-ui",
   "mcp-apps",
   "open-gen-ui",
+  "frontend-tools",
 ];
 
 const FEATURED_CATEGORY: FeatureCategory = {