refactor: Update loggedIn store type and streamline login/dashboard navigation logic

src/pages/login.astro

@@ -6,15 +6,14 @@ import BackgroundImage from "../components/BackgroundImage.astro";
 ---
 
 <NavbarLayout title={t("login.page")}>
-    <script>
+    <script is:inline data-astro-rerun>
         import { l } from "../util/util";
         import { navigate } from "astro:transitions/client";
         import { loggedIn } from "../components/repo/authv2";
-        import { get } from "svelte/store";
 
-        document.addEventListener("astro:page-load", () => {
+        loggedIn.subscribe((value) => {
             if (window.location.href.endsWith("/login") || window.location.href.endsWith("/login/")) {
-                if (get(loggedIn)) {
+                if (value) {
                     navigate(l("/dashboard"), { history: "replace" });
                 }
             }