refactor: add inventory dashboard link with appropriate attributes in the panel

client/src/App.jsx

@@ -16,6 +16,8 @@ function App() {
   const turtles = useTurtleStore((state) => state.getTurtleArray());
   const selectedTurtle = useTurtleStore((state) => state.getSelectedTurtle());
 
+  const inventoryDashboardUrl = import.meta.env.VITE_INVENTORY_DASHBOARD_URL || `${window.location.protocol}//${window.location.hostname}`;
+
   useEffect(() => {
     connect();
   }, [connect]);
@@ -52,6 +54,15 @@ function App() {
         </div>
         <div className="panel-container">
             <div className="panel-tabs">
+              <a
+                href={inventoryDashboardUrl}
+                className="cross-link-btn"
+                title="Open Inventory Manager Dashboard"
+                target="_blank"
+                rel="noopener noreferrer"
+              >
+                📦 Inventory
+              </a>
               <button 
                 className={panelTab === 'control' ? 'active' : ''}
                 onClick={() => setPanelTab('control')}