fix(web): lecteurs EPUB/PDF — gestion d'erreurs, worker pdf.js local

Composant ReaderError avec diagnostic et actions de repli, worker
pdf.js servi localement (pdfWorker) pour éviter les CDN, typage du
view foliate, navigation retour vers la fiche livre et styles lecteur
associés.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/web/src/reader/ReaderError.tsx

@@ -0,0 +1,53 @@
+import { ArrowLeft, Download, RotateCcw } from "lucide-react";
+import { navigate } from "../router";
+
+export function readerErrorMessage(error: unknown, fallback: string): string {
+  if (error instanceof Error && error.message.trim()) return error.message;
+  if (typeof error === "string" && error.trim()) return error;
+  return fallback;
+}
+
+export function ReaderError({
+  title,
+  detail,
+  technicalDetail,
+  downloadUrl,
+  backHref,
+  onRetry
+}: {
+  title: string;
+  detail: string;
+  technicalDetail?: string;
+  downloadUrl: string;
+  backHref: string;
+  onRetry: () => void;
+}) {
+  return (
+    <div className="reader-error">
+      <div>
+        <h2>{title}</h2>
+        <p>{detail}</p>
+      </div>
+      <div className="reader-error-actions">
+        <button className="ghost-button" onClick={onRetry}>
+          <RotateCcw size={16} />
+          Réessayer
+        </button>
+        <button className="ghost-button" onClick={() => navigate(backHref)}>
+          <ArrowLeft size={16} />
+          Retour à la fiche
+        </button>
+        <a className="ghost-button" href={downloadUrl} download>
+          <Download size={16} />
+          Télécharger
+        </a>
+      </div>
+      {technicalDetail && (
+        <details>
+          <summary>Détail technique</summary>
+          <pre>{technicalDetail}</pre>
+        </details>
+      )}
+    </div>
+  );
+}