web: edit virtual config sources with WASM core

web/workspace/src/routes/w/[workspaceId]/settings/configuration/+page.svelte

@@ -0,0 +1,27 @@
+<script lang="ts">
+  import ConfigSourceEditor from "$lib/workspace/config-source/ConfigSourceEditor.svelte";
+  import type { PageProps } from "./$types";
+
+  let { data }: PageProps = $props();
+  let workspaceId = $derived(data.workspace?.workspace_id ?? "");
+  let workspaceName = $derived(data.workspace?.display_name ?? "Workspace");
+</script>
+
+<svelte:head>
+  <title>Configuration | {workspaceName}</title>
+</svelte:head>
+
+<section class="settings-page">
+  <header class="page-header">
+    <div>
+      <p class="eyebrow">Workspace settings</p>
+      <h2>Configuration</h2>
+      <p>
+        Edit the Server-owned virtual Decodal source tree. Drafts stay in this browser;
+        the Server persists only a fully evaluated candidate.
+      </p>
+    </div>
+  </header>
+
+  <ConfigSourceEditor {workspaceId} />
+</section>