feat: markdown support for rss

package.json

@@ -46,6 +46,7 @@
     "@types/unist": "^3.0.3",
     "astro": "^5.18.1",
     "astro-icon": "^1.1.5",
+    "markdown-it": "14.1.1",
     "marked": "^17.0.4",
     "marked-shiki": "^1.2.1",
     "mdast-util-to-string": "^4.0.0",
@@ -64,6 +65,7 @@
     "@eslint-react/eslint-plugin": "^2.13.0",
     "@tailwindcss/forms": "^0.5.11",
     "@tailwindcss/typography": "^0.5.19",
+    "@types/markdown-it": "14.1.2",
     "eslint": "^10.0.3",
     "eslint-config-prettier": "^10.1.8",
     "eslint-plugin-astro": "^1.6.0",