Add Transmission/NZBGet and per-client paths and much more

Extend multi-download-client support to include Transmission and NZBGet and introduce per-client custom download paths. Adds protocol mapping and new client types, Transmission/NZBGet integration services, API CRUD and validation changes, UI components/modal updates and live path previews, and manager routing by protocol. Includes DB migrations (download_path on download_history, interactive_search_access on users), schema updates, and related processor/service fixes and tests to ensure backward compatibility and proper path resolution.

src/lib/services/job-queue.service.ts

@@ -7,6 +7,7 @@ import Queue, { Job as BullJob, JobOptions } from 'bull';
 import Redis from 'ioredis';
 import { prisma } from '../db';
 import { TorrentResult } from '../utils/ranking-algorithm';
+import { DownloadClientType } from '../interfaces/download-client.interface';
 import { RMABLogger } from '../utils/logger';
 
 const logger = RMABLogger.create('JobQueue');
@@ -59,7 +60,7 @@ export interface MonitorDownloadPayload extends JobPayload {
   requestId: string;
   downloadHistoryId: string;
   downloadClientId: string;
-  downloadClient: 'qbittorrent' | 'sabnzbd';
+  downloadClient: DownloadClientType;
 }
 
 export interface OrganizeFilesPayload extends JobPayload {
@@ -545,7 +546,7 @@ export class JobQueueService {
     requestId: string,
     downloadHistoryId: string,
     downloadClientId: string,
-    downloadClient: 'qbittorrent' | 'sabnzbd',
+    downloadClient: DownloadClientType,
     delaySeconds: number = 0
   ): Promise<string> {
     return await this.addJob(