fix(demo-ui): demoable apps launch in-frame; 'Not available in demo' label

- Register the 8 new placeholder apps in DEMO_MOCK_UI so they're launchable
  and installable in the demo.
- Demo bypasses the new-tab/tab-launch lists for demoable apps — they're
  served same-origin by the mock backend with no framing headers, so they
  render in the in-app session instead of opening broken localhost tabs.
- Non-demoable apps now say 'Not available in demo' instead of 'No demo'.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/views/Apps.vue

@@ -404,6 +404,7 @@ import {
   buildServiceCategories, useServiceCategories,
 } from './apps/appsConfig'
 import { getCuratedAppList, INSTALLED_ALIASES, type MarketplaceApp } from './marketplace/marketplaceData'
+import { IS_DEMO, isDemoApp } from '@/composables/useDemoIntro'
 
 const { t } = useI18n()
 const router = useRouter()
@@ -633,7 +634,9 @@ function launchAppNow(id: string) {
     }
     return
   }
-  if (!isMobile && pkg && opensInTab(id)) {
+  // Demo: demoable apps are served same-origin by the mock backend, so the
+  // tab-launch list (real apps with framing headers) doesn't apply.
+  if (!isMobile && pkg && opensInTab(id) && !(IS_DEMO && isDemoApp(id))) {
     const url = resolveRuntimeLaunchUrl(pkg)
     if (url) {
       window.open(url, '_blank', 'noopener,noreferrer')