Render markdown using the container API

This resolves images/links/etc just like it would when rendering to HTML in the /blog/* pages.

Note that container is an experimental API and may not work forever but since its a prerendered page idc to much

src/pages/rss.xml.ts

···
 import { getCollection } from "astro:content";
 import rss from "@astrojs/rss";
 import type { APIRoute } from "astro";
+import { experimental_AstroContainer } from "astro/container";
+
+const container = await experimental_AstroContainer.create();
 
 export const GET: APIRoute = async ({ site }) => {
   const posts = await getCollection("blog");
···
     site: site?.toString() ?? "",
     items: await Promise.all(
       posts.map(async (post) => {
-        const content = "TODO";
-
-        return {
+        const res = {
           title: post.data.title,
           description: post.data.bio,
           pubDate: post.data.pub,
           link: `/blog/${post.id}/`,
-          content: content,
         };
+
+        if (post.filePath) {
+          /* its ssg so dynamic imports are fine.
+            ../../ is bc it includes src/components 
+            so we need to go to project root */
+          /* @vite-ignore */
+          const { default: Component } = await import(`../../${post.filePath}`);
+          const content = await container.renderToString(Component);
+
+          return { ...res, content: content };
+        } else return res;
       }),
     ),
     // stylesheet: ``,