feat: suppression de livres + import insensible aux accents

- Ajout DELETE /books/:id : supprime le fichier physique, la thumbnail,
  le book en DB et queue un scan de la lib. Bouton avec confirmation
  sur la page de détail du livre.
- L'import torrent utilise unaccent() en SQL pour matcher les séries
  indépendamment des accents (ex: "les géants" = "les geants").
- Fallback filesystem avec strip_accents pour les séries sans livre en DB.
- Migration 0069: activation de l'extension PostgreSQL unaccent.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/backoffice/app/components/DeleteBookButton.tsx

@@ -0,0 +1,68 @@
+"use client";
+
+import { useState } from "react";
+import { createPortal } from "react-dom";
+import { useRouter } from "next/navigation";
+import { Button, Icon } from "./ui";
+import { useTranslation } from "@/lib/i18n/context";
+
+export function DeleteBookButton({ bookId, libraryId }: { bookId: string; libraryId: string }) {
+  const { t } = useTranslation();
+  const router = useRouter();
+  const [showConfirm, setShowConfirm] = useState(false);
+  const [deleting, setDeleting] = useState(false);
+
+  async function handleDelete() {
+    setDeleting(true);
+    setShowConfirm(false);
+    try {
+      const resp = await fetch(`/api/books/${bookId}`, { method: "DELETE" });
+      if (resp.ok) {
+        router.push(`/libraries/${libraryId}/series`);
+      }
+    } finally {
+      setDeleting(false);
+    }
+  }
+
+  return (
+    <>
+      <Button
+        variant="destructive"
+        size="sm"
+        onClick={() => setShowConfirm(true)}
+        disabled={deleting}
+      >
+        {deleting ? <Icon name="spinner" size="sm" className="animate-spin" /> : <Icon name="trash" size="sm" />}
+        <span className="ml-1.5">{t("bookDetail.delete")}</span>
+      </Button>
+
+      {showConfirm && createPortal(
+        <>
+          <div className="fixed inset-0 bg-black/30 backdrop-blur-sm z-50" onClick={() => setShowConfirm(false)} />
+          <div className="fixed inset-0 flex items-center justify-center z-50 p-4">
+            <div className="bg-card border border-border/50 rounded-xl shadow-2xl w-full max-w-sm overflow-hidden animate-in fade-in zoom-in-95 duration-200">
+              <div className="p-6">
+                <h3 className="text-lg font-semibold text-foreground mb-2">
+                  {t("bookDetail.delete")}
+                </h3>
+                <p className="text-sm text-muted-foreground">
+                  {t("bookDetail.confirmDelete")}
+                </p>
+              </div>
+              <div className="flex justify-end gap-2 px-6 pb-6">
+                <Button variant="outline" size="sm" onClick={() => setShowConfirm(false)}>
+                  {t("common.cancel")}
+                </Button>
+                <Button variant="destructive" size="sm" onClick={handleDelete}>
+                  {t("bookDetail.delete")}
+                </Button>
+              </div>
+            </div>
+          </div>
+        </>,
+        document.body
+      )}
+    </>
+  );
+}