fix: keep the welcome composer at the bottom

src/pages/Chat/CodingChatPanel.tsx

@@ -835,7 +835,7 @@ export function CodingChatPanel({
           </div>
         )}
 
-        {showWelcome ? <CodingStartHeading /> : targetConversationId
+        {showWelcome ? <><CodingStartHeading /><CommunityInvitation /></> : targetConversationId
           ? (
             <CodingConversationTimeline
               key={targetConversationId}
@@ -965,7 +965,6 @@ export function CodingChatPanel({
           }}
         />}
         </div>
-        {showWelcome && <CommunityInvitation />}
         </CodingChatBody>
       </div>