Add branding splash and simulator cycle timing

frontend/src/App.tsx

@@ -39,6 +39,7 @@ function FieldLabel({ label, error, children }: { label: string; error?: ReactNo
 }
 
 export default function App() {
+  const [showSplash, setShowSplash] = useState(true);
   const [dashboard, setDashboard] = useState<DashboardSnapshot | null>(null);
   const [orders, setOrders] = useState<ProductionOrder[]>([]);
   const [unqualifiedDowntimes, setUnqualifiedDowntimes] = useState<Downtime[]>([]);
@@ -77,6 +78,11 @@ export default function App() {
     return language === "fr" ? fr : en;
   }
 
+  useEffect(() => {
+    const timer = window.setTimeout(() => setShowSplash(false), 900);
+    return () => window.clearTimeout(timer);
+  }, []);
+
   const moduleTabs: Array<{ key: ModuleKey; label: string; description: string }> = [
     { key: "atelier", label: t("Workshop", "Atelier"), description: t("Machines view", "Vue machines") },
     { key: "machine", label: "Machine", description: t("Cycles and events", "Cycles et evenements") },
@@ -1118,13 +1124,34 @@ export default function App() {
     );
   }
 
+  if (showSplash) {
+    return (
+      <div className="splash-screen" aria-label="Plast Track">
+        <img src="/KSS.png" alt="KSS" />
+      </div>
+    );
+  }
+
   return (
     <div className={`app-shell ${isWorkshopMode && activeModule === "atelier" ? "app-shell--workshop" : ""}`}>
       <main className="workspace">
+        <aside className="demo-notice" role="note">
+          <strong>{t("Simulation and demonstration only", "Simulation et demonstration uniquement")}</strong>
+          <span>
+            {t(
+              "This web application is for simulation and demonstration. It must not be used as a validated production MES or safety system.",
+              "Cette application web est destinee a la simulation et a la demonstration. Elle ne doit pas etre utilisee comme MES de production valide ni comme systeme de securite.",
+            )}
+          </span>
+        </aside>
+
         <header className="hero">
-          <div>
-            <p className="eyebrow">Plast Track MVP</p>
-            <h1>{t("Workshop supervision", "Supervision atelier")}</h1>
+          <div className="brand-lockup">
+            <img className="brand-lockup__logo" src="/KSS.png" alt="KSS" />
+            <div>
+              <p className="eyebrow">Plast Track MVP</p>
+              <h1>{t("Workshop supervision", "Supervision atelier")}</h1>
+            </div>
           </div>
           <div className="hero__controls">
             <label className="language-select">