docs(cookbook): group Utilities under Expert, More

Move Value Help, Demo Output, and E-Mail into a new collapsible
Utilities subsection at the end of the Expert, More sidebar group.

Author: claude

docs/.vitepress/config.mjs

@@ -243,12 +243,18 @@ export default defineConfig({
               { text: "Statefulness", link: "/development/specific/statefulness" },
               { text: "WebSocket", link: "/development/specific/websocket" },
               { text: "Logout", link: "/configuration/logout" },
-              { text: "Value Help", link: "/development/specific/value_help" },
-              { text: "E-Mail", link: "/development/specific/email" },
-              { text: "Demo Output", link: "/development/specific/demo_output" },
               { text: "OData", link: "/development/model/odata" },
               { text: "App State", link: "/development/navigation/app_state" },
               { text: "Share, Bookmark", link: "/development/navigation/share" },
+              {
+                text: "Utilities",
+                collapsed: true,
+                items: [
+                  { text: "Value Help", link: "/development/specific/value_help" },
+                  { text: "Demo Output", link: "/development/specific/demo_output" },
+                  { text: "E-Mail", link: "/development/specific/email" },
+                ],
+              },
             ],
           },
         ],