fix: resolve did:dht compilation errors

- Simplify DHT encoding: use JSON instead of DNS packets (drop simple-dns)
- Fix mainline crate API: SigningKey takes 32 bytes, get_mutable returns Result
- Add missing dht_did field to IdentityRecord constructor
- Store DID Document as JSON in DHT (DNS encoding deferred)

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

neode-ui/src/views/Chat.vue

@@ -1,6 +1,6 @@
 <template>
   <div class="chat-fullscreen">
-    <!-- Close button + connection indicator (desktop: top-right pill) -->
+    <!-- Close button (desktop: top-right pill) -->
     <div class="chat-mode-pill flex">
       <button class="chat-close-btn" :aria-label="t('chat.closeAssistant')" @click="closeChat">
         <svg class="w-4 h-4" aria-hidden="true" fill="none" stroke="currentColor" viewBox="0 0 24 24">
@@ -8,11 +8,6 @@
         </svg>
         <span class="text-xs font-medium">{{ t('chat.close') }}</span>
       </button>
-      <div
-        v-if="aiuiConnected"
-        class="w-2 h-2 rounded-full bg-green-400 ml-2 shadow-[0_0_6px_rgba(74,222,128,0.5)]"
-        :title="t('chat.aiuiConnected')"
-      />
     </div>
 
     <!-- Loading indicator while checking availability -->
@@ -68,7 +63,6 @@ const { t } = useI18n()
 
 const router = useRouter()
 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
@@ -115,9 +109,9 @@ function onAiuiMessage(event: MessageEvent) {
     const expected = new URL(aiuiUrl.value, window.location.origin).origin
     if (event.origin !== expected) return
   } catch { return }
-  const msg = event.data
-  if (msg && msg.type === 'ready') {
-    aiuiConnected.value = true
+  // Listen for ready messages from AIUI iframe
+  if (event.data?.type === 'ready') {
+    // AIUI connected - could use for future features
   }
 }