feat: stream LLM responses (#2677)

Co-authored-by: Michael Neale <michael.neale@gmail.com>

ui/desktop/src/components/ChatView.tsx

@@ -786,7 +786,7 @@ function ChatContent({
               <SearchView>
                 {filteredMessages.map((message, index) => (
                   <div
-                    key={message.id || index}
+                    key={(message.id && `${message.id}-${message.content.length}`) || index}
                     className="mt-4 px-4"
                     data-testid="message-container"
                   >

ui/desktop/src/components/GooseMessage.tsx

@@ -130,7 +130,7 @@ export default function GooseMessage({
   ]);
 
   return (
-    <div className="goose-message flex w-[90%] justify-start opacity-0 animate-[appear_150ms_ease-in_forwards]">
+    <div className="goose-message flex w-[90%] justify-start">
       <div className="flex flex-col w-full">
         {/* Chain-of-Thought (hidden by default) */}
         {cotText && (