feat: Add book ratings and reviews managed via Directus CMS

Adds a new "Read Books" section below "Currently Reading" in the About
page. Book reviews with star ratings and comments are fetched from a
Directus CMS collection (book_reviews) and displayed with the existing
liquid design system. Includes i18n support (EN/DE), show more/less
toggle, and graceful fallback when the CMS collection does not exist yet.

https://claude.ai/code/session_017E8W9CcHFM5WQVHw74JP34

app/components/About.tsx

@@ -7,6 +7,7 @@ import { useLocale, useTranslations } from "next-intl";
 import type { JSONContent } from "@tiptap/react";
 import RichTextClient from "./RichTextClient";
 import CurrentlyReading from "./CurrentlyReading";
+import ReadBooks from "./ReadBooks";
 
 // Type definitions for CMS data
 interface TechStackItem {
@@ -389,6 +390,14 @@ const About = () => {
             >
               <CurrentlyReading />
             </motion.div>
+
+            {/* Read Books with Ratings */}
+            <motion.div
+              variants={fadeInUp}
+              className="mt-6"
+            >
+              <ReadBooks />
+            </motion.div>
           </motion.div>
         </div>
       </div>