feat: improve request history and tab persistence

- Add failed requests to history with error messages for better debugging
- Persist selected tab in URL hash and restore on page load
- Fix formatting of timeout parameter parsing

🤖 Generated with Claude CLI.

Co-Authored-By: Claude <noreply@anthropic.com>

client/src/App.tsx

@@ -59,7 +59,8 @@ const DEFAULT_REQUEST_TIMEOUT_MSEC = 10000;
 
 const params = new URLSearchParams(window.location.search);
 const PROXY_PORT = params.get("proxyPort") ?? "3000";
-const REQUEST_TIMEOUT = parseInt(params.get("timeout") ?? "") || DEFAULT_REQUEST_TIMEOUT_MSEC;
+const REQUEST_TIMEOUT =
+  parseInt(params.get("timeout") ?? "") || DEFAULT_REQUEST_TIMEOUT_MSEC;
 const PROXY_SERVER_URL = `http://localhost:${PROXY_PORT}`;
 
 const App = () => {
@@ -217,6 +218,12 @@ const App = () => {
     rootsRef.current = roots;
   }, [roots]);
 
+  useEffect(() => {
+    if (!window.location.hash) {
+      window.location.hash = "resources";
+    }
+  }, []);
+
   const pushHistory = (request: object, response?: object) => {
     setRequestHistory((prev) => [
       ...prev,
@@ -251,10 +258,14 @@ const App = () => {
         response = await mcpClient.request(request, schema, {
           signal: abortController.signal,
         });
+        pushHistory(request, response);
+      } catch (error) {
+        const errorMessage = error instanceof Error ? error.message : String(error);
+        pushHistory(request, { error: errorMessage });
+        throw error;
       } finally {
         clearTimeout(timeoutId);
       }
-      pushHistory(request, response);
 
       if (tabKey !== undefined) {
         clearError(tabKey);
@@ -485,7 +496,11 @@ const App = () => {
       <div className="flex-1 flex flex-col overflow-hidden">
         <div className="flex-1 overflow-auto">
           {mcpClient ? (
-            <Tabs defaultValue="resources" className="w-full p-4">
+            <Tabs
+              defaultValue={window.location.hash.slice(1) || "resources"}
+              className="w-full p-4"
+              onValueChange={(value) => (window.location.hash = value)}
+            >
               <TabsList className="mb-4 p-0">
                 <TabsTrigger value="resources">
                   <Files className="w-4 h-4 mr-2" />