fix(ui): first-login dashboard entrance restored + working Replay Intro

- playDashboardLoadOomph gated itself silent on the one entry that
  should be loud: onboarding is already flagged complete by the time the
  post-wizard dashboard mounts. force flag restores the full oomph there
  while keeping ordinary re-logins quiet (the intentional limit).
- OnboardingDone now hands Login a one-shot finale flag, so the login
  right after the wizard gets the full zoom + oomph even as a regular
  password login — which is exactly the demo flow (and TOTP logins).
- 'Replay intro' on the login screen actually replays: App.vue was
  instantly re-marking the intro as seen on onboarded nodes; an explicit
  one-shot replay flag now overrides every suppression rule (unit
  tested).

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

neode-ui/src/composables/useLoginSounds.ts

@@ -251,8 +251,15 @@ export function playKeyboardTypingSound() {
 }
 
 /** Gaming-style boot thud - soft impact when dashboard loads */
-export function playDashboardLoadOomph() {
-  if (!isFirstInstallPhase()) return
+/**
+ * @param force Play regardless of install phase. The first dashboard entry
+ * right after the onboarding wizard needs this: by then onboarding is already
+ * flagged complete in localStorage, so the isFirstInstallPhase() gate (which
+ * exists to keep ordinary re-logins quiet) would silence the one entrance
+ * that SHOULD be loud.
+ */
+export function playDashboardLoadOomph(force = false) {
+  if (!force && !isFirstInstallPhase()) return
   const ctx = getContext()
   if (!ctx) return