error modal when join url fails

src/chat/ChatContainer.svelte

@@ -39,11 +39,29 @@
         if (chat.isReady) {
           clearInterval(checkReady);
           chat.handleJoinServer(undefined, inviteCode);
-
+          
           // Clear URL parameter without reloading
           const url = new URL(window.location.href);
           url.searchParams.delete("invite");
           window.history.replaceState({}, document.title, url.pathname + url.search);
+
+          // Setup a one-time listener for the result of this specific link join
+          const cleanup = $effect.root(() => {
+            $effect(() => {
+               const status = chat.joinServerStatus;
+               if (status?.status === "error") {
+                 chat.confirmModal = {
+                   title: "Failed to Join Server",
+                   message: `The invite link was invalid or has expired. Error: ${status.error || 'Unknown error'}`,
+                   confirmText: "Close",
+                   onConfirm: () => {}
+                 };
+                 cleanup();
+               } else if (status?.status === "success") {
+                 cleanup();
+               }
+            });
+          });
         }
       }, 500);
     }