fix: build and test stability for design overhaul

Fixed missing types, import errors, and updated test suites to match the new editorial design. Verified Docker container build.

app/[locale]/books/page.tsx

@@ -1,7 +1,6 @@
 "use client";
 
-import { getLanguageAlternates, toAbsoluteUrl } from "@/lib/seo";
-import { BookOpen, ArrowLeft, Star } from "lucide-react";
+import { Star, ArrowLeft } from "lucide-react";
 import Link from "next/link";
 import Image from "next/image";
 import { useEffect, useState } from "react";