fix: update Toaster position and mark Sequencer link as WIP

src/App.tsx

@@ -163,7 +163,7 @@ function App() {
         <AuthProvider>
           <SocketProvider>
             <AppRoutes />
-            <Toaster richColors position='top-right' />
+            <Toaster richColors position='top-center' />
           </SocketProvider>
         </AuthProvider>
       </ThemeProvider>

src/components/AppSidebar.tsx

@@ -49,9 +49,9 @@ export function AppSidebar({ showCompactPlayer = false }: AppSidebarProps) {
           <NavItem href="/" icon={Home} title="Dashboard" />
           <NavItem href="/sounds" icon={Music} title="Sounds" />
           <NavItem href="/playlists" icon={PlayCircle} title="Playlists" />
-          <NavItem href="/sequencer" icon={AudioLines} title="Sequencer" />
           <NavItem href="/extractions" icon={Download} title="Extractions" />
           <NavItem href="/schedulers" icon={CalendarClock} title="Schedulers" />
+          <NavItem href="/sequencer" icon={AudioLines} title="Sequencer (WIP)" />
         </NavGroup>
 
         {user.role === 'admin' && (