feat: update back button logic

Instead of saving back url in the param, save the
back url info inside session.

src/pages/archives/index.astro

@@ -29,8 +29,6 @@ const months = [
   "November",
   "December",
 ];
-
-const backUrl = SITE.showBackButton ? `?from=${Astro.url.pathname}` : "/";
 ---
 
 <Layout title={`Archives | ${SITE.title}`}>
@@ -72,10 +70,7 @@ const backUrl = SITE.showBackButton ? `?from=${Astro.url.pathname}` : "/";
                           )
                       )
                       .map(({ data, id }) => (
-                        <Card
-                          href={`/posts/${id}${backUrl}`}
-                          frontmatter={data}
-                        />
+                        <Card href={`/posts/${id}`} frontmatter={data} />
                       ))}
                   </ul>
                 </div>
@@ -84,6 +79,5 @@ const backUrl = SITE.showBackButton ? `?from=${Astro.url.pathname}` : "/";
         ))
     }
   </Main>
-
   <Footer />
 </Layout>

src/pages/index.astro

@@ -22,7 +22,7 @@ const recentPosts = sortedPosts.filter(({ data }) => !data.featured);
 
 <Layout>
   <Header />
-  <main id="main-content">
+  <main id="main-content" data-layout="index">
     <section id="hero" class="pt-8 pb-6">
       <h1 class="my-4 inline-block text-4xl font-bold sm:my-8 sm:text-5xl">
         Mingalaba
@@ -119,3 +119,13 @@ const recentPosts = sortedPosts.filter(({ data }) => !data.featured);
   </main>
   <Footer />
 </Layout>
+
+<script>
+  document.addEventListener("astro:page-load", () => {
+    const indexLayout = (document.querySelector("#main-content") as HTMLElement)
+      ?.dataset?.layout;
+    if (indexLayout) {
+      sessionStorage.setItem("backUrl", "/");
+    }
+  });
+</script>