release(v1.7.34-alpha): re-seed onboarding cache + rotating login bg + drop re-login zoom

- useOnboarding.ts: when the backend gives a definitive answer
  (true/false, not a null retry failure), re-seed the
  neode_onboarding_complete localStorage flag accordingly. Fixes the
  case where a user clears site data on an already-onboarded node —
  OnboardingWrapper's useVideoBackground computed reads localStorage
  synchronously, so without this re-seed the intro video would fire
  again on /login even though RootRedirect correctly sent them
  straight to /login.
- OnboardingWrapper.vue: login background now rotates through
  bg-intro-1..6 on each /login mount, with the current index
  persisted to localStorage (neode_login_bg_idx) so subsequent
  logouts advance rather than repeat the same image.
- Dashboard.vue: subsequent-login branch drops the 1.2s showZoomIn
  entirely. Only the first dashboard entry after onboarding plays
  the full zoom + glitch reveal; every re-login now just fades in
  with the welcome typing (~300ms).

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

neode-ui/src/views/OnboardingWrapper.vue

@@ -122,7 +122,32 @@ const routeBackgrounds: Record<string, string> = {
   '/login': 'bg-intro.jpg' // Video loops from splash (same as intro)
 }
 
-const loginBackground = 'bg-intro-1.jpg'
+// Rotate the login background so the lock screen doesn't look
+// identical on every logout. Cycles through bg-intro-1..6 using a
+// counter persisted to localStorage so subsequent visits advance.
+const LOGIN_BACKGROUNDS = [
+  'bg-intro-1.jpg',
+  'bg-intro-2.jpg',
+  'bg-intro-3.jpg',
+  'bg-intro-4.jpg',
+  'bg-intro-5.jpg',
+  'bg-intro-6.jpg',
+]
+function pickNextLoginBackground(): string {
+  try {
+    const raw = localStorage.getItem('neode_login_bg_idx')
+    const prev = raw !== null ? parseInt(raw, 10) : -1
+    const next = (Number.isFinite(prev) ? prev + 1 : 0) % LOGIN_BACKGROUNDS.length
+    localStorage.setItem('neode_login_bg_idx', String(next))
+    return LOGIN_BACKGROUNDS[next]!
+  } catch {
+    return LOGIN_BACKGROUNDS[Math.floor(Math.random() * LOGIN_BACKGROUNDS.length)]!
+  }
+}
+const loginBackground = ref(pickNextLoginBackground())
+watch(() => route.path, (p) => {
+  if (p === '/login') loginBackground.value = pickNextLoginBackground()
+})
 
 // Restore video time from splash screen for seamless transition
 function restoreVideoTime() {