Fix local images and em dash rendering

sites/poetry/astro.config.mjs

@@ -2,6 +2,7 @@
 import { defineConfig } from "astro/config";
 import mdx from "@astrojs/mdx";
 import rehypeKatex from "rehype-katex";
+import remarkGfm from "remark-gfm";
 import remarkMath from "remark-math";
 import sitemap from "@astrojs/sitemap";
 
@@ -9,9 +10,19 @@ import react from "@astrojs/react";
 // @ts-ignore - TailwindCSS v4 Vite plugin has type compatibility issues with Astro
 import tailwindcss from "@tailwindcss/vite";
 import remarkCallouts from "./src/remark/callouts.mjs";
+import remarkCodeFenceLanguages from "./src/remark/code-fence-languages.mjs";
+import remarkInlineFootnotes from "./src/remark/inline-footnotes.mjs";
+import remarkTypography from "./src/remark/typography.mjs";
 import { ACTIVE_BLOG_SITE } from "./src/blog-sites.js";
 
-const remarkPlugins = [remarkMath, remarkCallouts];
+const remarkPlugins = [
+  remarkGfm,
+  remarkInlineFootnotes,
+  remarkCodeFenceLanguages,
+  remarkMath,
+  remarkTypography,
+  remarkCallouts,
+];
 const rehypePlugins = [rehypeKatex];
 
 // https://astro.build/config