chore: init svelte rewrite scaffold

src/components/layout/Layout.svelte

@@ -0,0 +1,44 @@
+<script lang="ts">
+  import { navPage, activeManga } from "../../store";
+  import Sidebar    from "./Sidebar.svelte";
+  import Library    from "../pages/Library.svelte";
+  import SeriesDetail from "../pages/SeriesDetail.svelte";
+  import History    from "../history/History.svelte";
+  import Search     from "../search/Search.svelte";
+  import Explore    from "../pages/Explore.svelte";
+  import Downloads  from "../downloads/Downloads.svelte";
+  import Extensions from "../pages/Extensions.svelte";
+</script>
+
+<div class="root">
+  <Sidebar />
+  <main class="main">
+    {#if $activeManga}
+      <SeriesDetail />
+    {:else if $navPage === "library"}
+      <Library />
+    {:else if $navPage === "search"}
+      <Search />
+    {:else if $navPage === "history"}
+      <History />
+    {:else if $navPage === "explore" || $navPage === "sources"}
+      <Explore />
+    {:else if $navPage === "downloads"}
+      <Downloads />
+    {:else if $navPage === "extensions"}
+      <Extensions />
+    {:else}
+      <Library />
+    {/if}
+  </main>
+</div>
+
+<style>
+  .root { display: flex; height: 100%; background: var(--bg-base); overflow: hidden; }
+  .main {
+    flex: 1; overflow: hidden;
+    background: var(--bg-surface);
+    transform: translateZ(0);
+    contain: layout style;
+  }
+</style>