Refactor login flow to return redirect URL instead of direct navigation

Move navigation responsibility from useAuth composable to login page
component for better separation of concerns and component control.

pages/login.vue

@@ -185,10 +185,13 @@ const handleLogin = async () => {
       rememberMe: credentials.value.rememberMe
     });
 
-    if (!result.success) {
+    if (result.success) {
+      // Handle redirect from the component
+      console.log('🔄 Login successful, redirecting to:', result.redirectTo);
+      await navigateTo(result.redirectTo || '/dashboard');
+    } else {
       loginError.value = result.error || 'Login failed. Please check your credentials and try again.';
     }
-    // If successful, the login method will handle the redirect
   } catch (error: any) {
     console.error('Login error:', error);
     loginError.value = authError.value || 'Login failed. Please check your credentials and try again.';