fix: parse overlay markdown body to HTML before storing

The overlay body was stored as raw markdown but rendered via raw() on
detail pages, which expects HTML. Now uses marked.parse() during load
so headings, emphasis, and paragraphs render correctly.

Author: danielnaab

src/catalog/overlays.ts

@@ -1,4 +1,5 @@
 import { parse as parseYaml } from 'yaml'
+import { marked } from 'marked'
 import type { Overlay } from './types'
 
 const FRONTMATTER_RE = /^---\n([\s\S]*?)\n---\n?([\s\S]*)$/
@@ -20,7 +21,7 @@ export async function loadOverlay(path: string): Promise<Overlay | null> {
     summary: stringOrUndefined(frontMatter.summary),
     highlights: stringArrayOrUndefined(frontMatter.highlights),
     related: stringArrayOrUndefined(frontMatter.related),
-    body: body || undefined,
+    body: body ? (marked.parse(body, { async: false }) as string) : undefined,
   }
 }