feat(demo): app launch UIs, "No demo" gating, onboarding skip, 12 nodes

App launching (DEMO):
- resolveAppUrl routes every app to its demo target: mock UIs for Bitcoin Core,
  ElectrumX, Fedimint (served by the backend), IndeeHub → iframe indee.tx1138.com,
  Mempool → mempool.space/testnet (new tab); all others → a generic "Demo preview"
  notice page.
- Non-demoable apps show a disabled "No demo" install button (marketplace details,
  app grid, featured apps).

Onboarding:
- Demo treats the visitor as fully set up so the onboarding WIZARD (seed/identity)
  is never forced; the welcome intro still replays per day. Intro CTA goes straight
  to login; wizard entry points + login restart-onboarding link hidden in demo.

Network:
- federation.list-nodes now returns 12 trusted/federated nodes (9 trusted, 3
  observer); transport.peers already at 5.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

neode-ui/src/stores/appLauncher.ts

@@ -4,6 +4,7 @@ import { rpcClient } from '@/api/rpc-client'
 import router from '@/router'
 import { recordAppLaunch } from '@/utils/appUsage'
 import { requestExternalOpen } from '@/api/remote-relay'
+import { IS_DEMO, isDemoExternal, demoAppUrl } from '@/composables/useDemoIntro'
 
 /**
  * Open a URL in a new browser tab — but if a companion (phone) is currently
@@ -222,6 +223,12 @@ export const useAppLauncherStore = defineStore('appLauncher', () => {
   function openSession(appId: string) {
     recordAppLaunch(appId)
     const mobile = isMobileViewport()
+    // Demo: apps backed by a real external site that blocks iframing (mempool.space)
+    // open in a new tab; everything else demoable renders in the in-app session.
+    if (IS_DEMO && isDemoExternal(appId)) {
+      const ext = demoAppUrl(appId)
+      if (ext) { openExternal(ext); return }
+    }
     const launchUrl = NEW_TAB_APP_IDS.has(appId) ? directAppUrl(appId) : null
     if (launchUrl && !mobile) {
       openExternal(launchUrl)