Add post preambles that only show on the post page and not on index pages

lib/metadata.ts

@@ -23,6 +23,7 @@ export interface PostMetadata extends Metadata {
 	wordCount?: number;
 	excerpt?: string;
 	uuid: string;
+	preamble?: string;
 }
 
 export async function get(path: string): Promise<Page> {

site/layouts/article.html.ejs

@@ -9,6 +9,9 @@ metadata.layout = "default.html.ejs"
 	</h1>
 	<%- include("../includes/article-meta.html.ejs", { metadata }) %>
 	<div class="article-content" itemprop="articleBody">
+		<% if (metadata.preamble) { %>
+			<%- metadata.preamble %>
+		<% } %>
 		<%- content %>
 	</div>
     <details id="comments-container">