feat: add LoginPage and ScrollToTop components with App routing integration

src/App.tsx

@@ -30,12 +30,14 @@ import { LabelPreviewPage } from './pages/dashboard/LabelPreviewPage';
 import { StorePreviewPage } from './pages/StorePreviewPage';
 import { LoadingProvider } from './context/LoadingContext';
 import { Preloader } from './components/common/Preloader';
+import { ScrollToTop } from './components/common/ScrollToTop';
 
 export const App: React.FC = () => {
   return (
     <SellerProvider>
       <LoadingProvider>
         <Router>
+          <ScrollToTop />
           <Preloader />
           <Routes>
             {/* Public Marketing & Informational Zone */}

src/components/common/ScrollToTop.tsx

@@ -0,0 +1,27 @@
+import React, { useEffect } from 'react';
+import { useLocation } from 'react-router-dom';
+
+/**
+ * ScrollToTop component listens for route changes and automatically resets
+ * the viewport scroll position to the top of the page.
+ */
+export const ScrollToTop: React.FC = () => {
+  const { pathname, search } = useLocation();
+
+  useEffect(() => {
+    window.scrollTo({
+      top: 0,
+      left: 0,
+      behavior: 'instant' as ScrollBehavior,
+    });
+
+    if (document.documentElement) {
+      document.documentElement.scrollTop = 0;
+    }
+    if (document.body) {
+      document.body.scrollTop = 0;
+    }
+  }, [pathname, search]);
+
+  return null;
+};

src/pages/LoginPage.tsx

@@ -50,8 +50,17 @@ export const LoginPage: React.FC<LoginPageProps> = ({ initialMode }) => {
     } else if (location.pathname === '/login') {
       setMode('login');
     }
+    window.scrollTo({ top: 0, left: 0, behavior: 'instant' });
+    if (document.documentElement) document.documentElement.scrollTop = 0;
+    if (document.body) document.body.scrollTop = 0;
   }, [location.pathname]);
 
+  useEffect(() => {
+    window.scrollTo({ top: 0, left: 0, behavior: 'instant' });
+    if (document.documentElement) document.documentElement.scrollTop = 0;
+    if (document.body) document.body.scrollTop = 0;
+  }, [mode]);
+
   // Login state
   const [mobileNumber, setMobileNumber] = useState('');
   const [loginOtp, setLoginOtp] = useState('');