feat: render changelog as markdown in about panel (#33)

## Summary

- Installs `react-markdown@10.1.0` in `apps/web`
- Replaces the `<pre>` tag in the changelog section with the `<Markdown>` component for proper rendering
- Updates CSS to style markdown elements (paragraphs, lists, headings, code blocks, links, bold text)

Closes #31

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #33
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

apps/web/package.json

@@ -13,7 +13,8 @@
   "dependencies": {
     "@elysium/types": "workspace:*",
     "react": "19.0.0",
-    "react-dom": "19.0.0"
+    "react-dom": "19.0.0",
+    "react-markdown": "10.1.0"
   },
   "devDependencies": {
     "@nhcarrigan/eslint-config": "5.2.0",