Add extensible notification providers + UI/API

Introduce a provider-based notification system and wire it through the API and admin UI. Added INotificationProvider + notification service implementation and providers (apprise, discord, ntfy, pushover), plus a GET /api/admin/notifications/providers endpoint to expose provider metadata. Refactored code to use provider type strings (removed enum coupling), updated masking/encryption calls, and simplified the test notification endpoint to accept backendId or type+config and call sendToBackend directly.

UI: NotificationsTab now fetches provider metadata and renders provider cards and dynamic config forms (fields driven by provider metadata). Added config field rendering, improved backend cards, and edit/delete actions.

APIs: New providers route, updated admin notification CRUD routes to validate provider types dynamically, updated test route schema. Added download-client categories POST API to fetch categories from clients and wired postImportCategory handling in download-client routes.

Other notable changes: BookDate now fetches Claude models dynamically from Anthropic's Models API; added paginated model fetch helper. Added ALLOW_WEAK_PASSWORD flag exposure to auth providers and password change logic. Doc updates and various tests added/updated. File-organization doc clarifies EPERM fix using stream-based copy.

src/lib/processors/organize-files.processor.ts

@@ -180,6 +180,9 @@ export async function processOrganizeFiles(payload: OrganizeFilesPayload): Promi
       },
     });
 
+    // Apply post-import category to torrent client if configured
+    await applyPostImportCategory(requestId, logger);
+
     logger.info(`Request ${requestId} completed successfully - status: downloaded`, {
       success: true,
       message: 'Files organized successfully',
@@ -606,6 +609,9 @@ async function processEbookOrganization(
     },
   });
 
+  // Apply post-import category to torrent client if configured
+  await applyPostImportCategory(requestId, logger);
+
   logger.info(`Ebook request ${requestId} completed - status: downloaded (terminal)`);
 
   // Send "available" notification for ebooks at downloaded state
@@ -753,6 +759,59 @@ async function createEbookRequestIfEnabled(
   }
 }
 
+// =========================================================================
+// POST-IMPORT CATEGORY
+// =========================================================================
+
+/**
+ * Apply post-import category to the download client after successful import.
+ * Only applies to torrent clients (qBittorrent/Transmission) when configured.
+ * Non-fatal: logs a warning on failure but does not fail the job.
+ */
+async function applyPostImportCategory(
+  requestId: string,
+  logger: RMABLogger
+): Promise<void> {
+  try {
+    // Get download history to find client type and download ID
+    const downloadHistory = await prisma.downloadHistory.findFirst({
+      where: { requestId },
+      orderBy: { createdAt: 'desc' },
+    });
+
+    if (!downloadHistory?.downloadClientId || !downloadHistory?.downloadClient) {
+      return;
+    }
+
+    const clientType = downloadHistory.downloadClient as DownloadClientType;
+
+    // Only applies to torrent clients
+    const protocol = CLIENT_PROTOCOL_MAP[clientType];
+    if (protocol !== 'torrent') {
+      return;
+    }
+
+    // Get client config and check if postImportCategory is set
+    const configService = getConfigService();
+    const manager = getDownloadClientManager(configService);
+    const clients = await manager.getAllClients();
+    const clientConfig = clients.find(c => c.enabled && c.type === clientType);
+
+    if (!clientConfig?.postImportCategory) {
+      return;
+    }
+
+    logger.info(`Applying post-import category "${clientConfig.postImportCategory}" to download ${downloadHistory.downloadClientId}`);
+
+    const service = await manager.createClientFromConfig(clientConfig);
+    await service.setCategory(downloadHistory.downloadClientId, clientConfig.postImportCategory);
+
+    logger.info(`Post-import category applied successfully`);
+  } catch (error) {
+    logger.warn(`Failed to apply post-import category: ${error instanceof Error ? error.message : String(error)}`);
+  }
+}
+
 // =========================================================================
 // DOWNLOAD CLEANUP
 // =========================================================================