Add manual-import and download-access features

Introduce manual import workflow and download permission support. Adds a Prisma migration and schema field (users.download_access) to track per-user download access, and updates admin UI to toggle global and per-user download access. Implements new APIs: filesystem browse, manual-import endpoint, download-access settings, audiobook download-status, and on-demand download-token generation. Adds frontend components for manual import and related tests, plus documentation for the manual-import feature and the documentation-agent prompt. Key files: prisma/migrations/20260212000000_add_download_access_permission/migration.sql, prisma/schema.prisma, src/app/api/admin/filesystem/browse/route.ts, src/app/api/admin/manual-import/route.ts, src/app/api/admin/settings/download-access/route.ts, src/app/api/requests/[id]/download-token/route.ts, src/app/api/audiobooks/[asin]/download-status/route.ts, and updated admin users pages/components and permissions util.

src/components/audiobooks/AudiobookCard.tsx

@@ -56,8 +56,13 @@ export function AudiobookCard({
   const [showToast, setShowToast] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const [showModal, setShowModal] = useState(false);
+  const [localRequestStatus, setLocalRequestStatus] = useState<string | undefined>(undefined);
 
-  const status = getStatusConfig(audiobook);
+  // Build a display-only audiobook with the local status override
+  const displayAudiobook = localRequestStatus !== undefined
+    ? { ...audiobook, requestStatus: localRequestStatus }
+    : audiobook;
+  const status = getStatusConfig(displayAudiobook);
 
   const handleRequest = async (e: React.MouseEvent) => {
     e.stopPropagation();
@@ -69,6 +74,7 @@ export function AudiobookCard({
 
     try {
       await createRequest(audiobook);
+      setLocalRequestStatus('pending');
       setShowToast(true);
       setTimeout(() => setShowToast(false), 2500);
       onRequestSuccess?.();
@@ -240,8 +246,9 @@ export function AudiobookCard({
         isOpen={showModal}
         onClose={() => setShowModal(false)}
         onRequestSuccess={onRequestSuccess}
-        isRequested={audiobook.isRequested}
-        requestStatus={audiobook.requestStatus}
+        onStatusChange={(newStatus) => setLocalRequestStatus(newStatus)}
+        isRequested={audiobook.isRequested || localRequestStatus !== undefined}
+        requestStatus={displayAudiobook.requestStatus}
         isAvailable={audiobook.isAvailable}
         requestedByUsername={audiobook.requestedByUsername}
         hasReportedIssue={audiobook.hasReportedIssue}