fix: auto-select first conversation + remove chat avatars

src/pages/TaskAssistant.tsx

@@ -41,6 +41,13 @@ function ChatPage() {
     try { setConversations(await listConversations()) } catch { /* */ }
   }, [])
   useEffect(() => { loadConversations() }, [loadConversations])
+
+  // Auto-select first conversation on load
+  useEffect(() => {
+    if (!activeId && conversations.length > 0) {
+      switchConversation(conversations[0].id)
+    }
+  }, [conversations, activeId])
   useEffect(() => { messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' }) }, [messages])
 
   const switchConversation = useCallback(async (id: string) => {