feat: add search in page for books, magazines and other docs

app/(app)/books/ej/[chapter]/page.tsx

@@ -18,6 +18,7 @@ import { buttonVariants } from "@/components/ui/button";
 import { ChevronLeft, ChevronRight } from "lucide-react";
 import { cn } from "@/lib/utils";
 import { MobileNav, type MobileNavGroup } from "@/components/layout/mobile-nav";
+import { FindInPage } from "@/components/layout/find-in-page";
 
 // ---------------------------------------------------------------------------
 // Metadata
@@ -77,12 +78,15 @@ export default async function EjChapterPage({
         >
           ← Easy Journey to Other Planets
         </Link>
-        <h1 className="mt-3 text-2xl font-bold text-foreground">
-          {chapterNum != null && (
-            <span className="text-primary">Chapter {chapterNum}: </span>
-          )}
-          {content.title}
-        </h1>
+        <div className="mt-3 flex items-start justify-between gap-3">
+          <h1 className="text-2xl font-bold text-foreground">
+            {chapterNum != null && (
+              <span className="text-primary">Chapter {chapterNum}: </span>
+            )}
+            {content.title}
+          </h1>
+          <FindInPage targetId="book-content" className="shrink-0 mt-0.5" />
+        </div>
       </PageHeader>
 
       <div className="max-w-5xl mx-auto flex">
@@ -100,7 +104,7 @@ export default async function EjChapterPage({
           />
 
           {/* Content */}
-          <Card>
+          <Card id="book-content">
             <CardContent className="py-8 px-6 sm:px-8">
               <div className="space-y-4">
                 {content.paragraphs.map((paragraph, i) => (