feat: onboarding polish, splash screen, controller nav, dev script

Onboarding flow:
- Intro: improved layout and transitions
- DID: better card styling and responsiveness
- Path: added visual enhancements
- Backup/Identity/Verify: streamlined markup
- SplashScreen component added

UI:
- Controller navigation improvements (useControllerNav)
- Style.css refinements

Backend:
- Runtime package fix

Dev:
- dev-start.sh improvements

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/src/components/SplashScreen.vue

@@ -277,6 +277,13 @@ if (!storedSeenIntro && isOnDashboard) {
   localStorage.setItem('neode_intro_seen', '1')
 }
 
+function handleEnterKey(e: KeyboardEvent) {
+  if (e.key === 'Enter' && showTapToStart.value && !tapStartTransitioning.value) {
+    e.preventDefault()
+    handleTapToStart()
+  }
+}
+
 function onIntroLogoHover() {
   introLogoHover.value = true
   if (!tapStartTransitioning.value) playKeyboardTypingSound()
@@ -465,10 +472,13 @@ onMounted(() => {
     showSplash.value = false
     document.body.classList.add('splash-complete')
     emit('complete')
+  } else {
+    window.addEventListener('keydown', handleEnterKey)
   }
 })
 
 onBeforeUnmount(() => {
+  window.removeEventListener('keydown', handleEnterKey)
   if (introTypingTimeout) {
     clearTimeout(introTypingTimeout)
     introTypingTimeout = null