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/admin/users/UserPermissionsModal.tsx

@@ -15,6 +15,7 @@ interface UserPermissionsUser {
   role: 'user' | 'admin';
   autoApproveRequests: boolean | null;
   interactiveSearchAccess: boolean | null;
+  downloadAccess: boolean | null;
 }
 
 interface UserPermissionsModalProps {
@@ -23,8 +24,10 @@ interface UserPermissionsModalProps {
   user: UserPermissionsUser | null;
   globalAutoApprove: boolean;
   globalInteractiveSearch: boolean;
+  globalDownloadAccess: boolean;
   onToggleAutoApprove: (user: UserPermissionsUser, newValue: boolean) => void;
   onToggleInteractiveSearch: (user: UserPermissionsUser, newValue: boolean) => void;
+  onToggleDownloadAccess: (user: UserPermissionsUser, newValue: boolean) => void;
 }
 
 interface PermissionToggleProps {
@@ -86,8 +89,10 @@ export function UserPermissionsModal({
   user,
   globalAutoApprove,
   globalInteractiveSearch,
+  globalDownloadAccess,
   onToggleAutoApprove,
   onToggleInteractiveSearch,
+  onToggleDownloadAccess,
 }: UserPermissionsModalProps) {
   if (!user) return null;
 
@@ -103,6 +108,11 @@ export function UserPermissionsModal({
   const isSearchDisabled = isAdmin || isSearchGlobalOverride;
   const searchValue = isAdmin ? true : isSearchGlobalOverride ? true : (user.interactiveSearchAccess ?? false);
 
+  // Download Access resolution
+  const isDownloadGlobalOverride = !isAdmin && globalDownloadAccess;
+  const isDownloadDisabled = isAdmin || isDownloadGlobalOverride;
+  const downloadValue = isAdmin ? true : isDownloadGlobalOverride ? true : (user.downloadAccess ?? false);
+
   const getDisabledMessage = (isAdminUser: boolean, isGlobalOverride: boolean, adminMessage: string, globalMessage: string): string | undefined => {
     if (isAdminUser) return adminMessage;
     if (isGlobalOverride) return globalMessage;
@@ -176,6 +186,21 @@ export function UserPermissionsModal({
               description="When enabled, this user can manually search and select torrents and ebooks"
               onToggle={() => onToggleInteractiveSearch(user, !searchValue)}
             />
+
+            {/* Download Access Permission */}
+            <PermissionToggle
+              label="Download Access"
+              ariaLabel="Download Access"
+              value={downloadValue}
+              disabled={isDownloadDisabled}
+              disabledMessage={getDisabledMessage(
+                isAdmin, isDownloadGlobalOverride,
+                'Admins always have download access',
+                'Controlled by global download access setting'
+              )}
+              description="When enabled, this user can download audiobook files directly"
+              onToggle={() => onToggleDownloadAccess(user, !downloadValue)}
+            />
           </div>
         </div>
       </div>