refactor: update dependencies and remove unused code

- Added new dependencies: `adler2`, `crc32fast`, `flate2`, `miniz_oxide`, and `libredox`.
- Updated existing dependencies: `tokio-rustls` to version 0.26.4 and `filetime` to version 0.2.27.
- Removed the `backup.rs` file as it is no longer needed.
- Introduced tests for configuration and credential management.
- Enhanced the `identity` module to generate W3C compliant DID documents.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

neode-ui/src/views/Chat.vue

@@ -22,12 +22,12 @@
       </svg>
     </button>
 
-    <!-- Loading indicator while iframe loads -->
+    <!-- Loading indicator while checking availability or iframe loads -->
     <Transition name="fade">
-      <div v-if="aiuiUrl && !aiuiConnected" class="chat-loading" role="status" aria-live="polite">
+      <div v-if="aiuiAvailable === null || (aiuiUrl && !aiuiConnected)" class="chat-loading" role="status" aria-live="polite">
         <div class="glass-card p-8 flex flex-col items-center gap-4">
           <div class="chat-loading-spinner" aria-hidden="true" />
-          <p class="text-sm text-white/60">{{ t('chat.loadingAssistant') }}</p>
+          <p class="text-sm text-white/60">{{ aiuiAvailable === null ? t('chat.loadingAssistant') : t('chat.loadingAssistant') }}</p>
         </div>
       </div>
     </Transition>
@@ -78,13 +78,35 @@ const aiuiFrame = ref<HTMLIFrameElement | null>(null)
 const aiuiConnected = ref(false)
 let broker: ContextBroker | null = null
 
+const aiuiAvailable = ref<boolean | null>(null) // null = checking, true/false = result
+
 const aiuiUrl = computed(() => {
   const envUrl = import.meta.env.VITE_AIUI_URL
   if (envUrl) return `${envUrl}?embedded=true`
-  if (import.meta.env.PROD) return '/aiui/?embedded=true'
+  // In production, only return the URL if we've confirmed AIUI files exist
+  if (import.meta.env.PROD && aiuiAvailable.value === true) return '/aiui/?embedded=true'
   return ''
 })
 
+/** Check if AIUI is actually deployed by fetching its index.html */
+async function checkAiuiAvailable() {
+  if (import.meta.env.VITE_AIUI_URL) {
+    aiuiAvailable.value = true
+    return
+  }
+  if (!import.meta.env.PROD) {
+    aiuiAvailable.value = false
+    return
+  }
+  try {
+    const res = await fetch('/aiui/', { method: 'HEAD' })
+    // If we get HTML back (200), AIUI is deployed. If 404/403, it's not.
+    aiuiAvailable.value = res.ok
+  } catch {
+    aiuiAvailable.value = false
+  }
+}
+
 function closeChat() {
   if (window.history.length > 1) {
     router.back()
@@ -106,8 +128,9 @@ function onAiuiMessage(event: MessageEvent) {
   }
 }
 
-onMounted(() => {
+onMounted(async () => {
   window.addEventListener('message', onAiuiMessage)
+  await checkAiuiAvailable()
   if (aiuiUrl.value) {
     broker = new ContextBroker(aiuiFrame, aiuiUrl.value)
     broker.start()