fix: ukloni dupli toast provider u layoutu

Uklonjen je paralelni ToastProvider iz Layout.astro kako bi ostao samo postojeći ToastContainer (nanostore), čime se sprječava hydration crash i null.map greška na /putni-nalozi.\n\nCo-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/layouts/Layout.astro

@@ -8,7 +8,6 @@ import Toast from '../components/ui/Toast.jsx';
 import ToastTrigger from '../components/ToastTrigger.jsx';
 import NetworkGuard from '../components/ui/NetworkGuard.jsx';
 import Navbar from '../components/Navbar.jsx';
-import ToastProvider from '../components/toast/ToastProvider';
 
 interface Props {
   title: string;
@@ -54,7 +53,6 @@ const isDev = import.meta.env.DEV;
 
     {!isAuthPage && <NetworkGuard client:only="preact" />}
     <Toast client:load />
-    <ToastProvider client:load />
     {!isAuthPage && isDev && <ToastTrigger client:load />}
     {!isAuthPage && <Navbar client:load minimal={minimalNav} />}