Add watched series/authors feature

Introduce watched lists for series and authors end-to-end.

- Add DB migration to create watched_series and watched_authors tables with indexes and foreign keys.
- Implement API routes: GET/POST for listing/adding and DELETE by id for both /api/user/watched-series and /api/user/watched-authors. Validation, ownership checks, and immediate targeted job triggers are included.
- Add client hooks (useWatchedSeries, useWatchedAuthors) with add/delete helpers and SWR revalidation.
- Add UI components: WatchButton (toggle/confirm) and WatchedListsSection for profile display and removal UX.
- Add processor (check-watched-lists.processor) and service (watched-lists.service) to scrape Audible, deduplicate, check library ownership, and auto-create requests; supports targeted checks for newly watched items.
- Include tests for the watched-lists service.

These changes implement the watched-lists feature to let users watch series/authors and have the system automatically detect and request new releases.

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

@@ -27,6 +27,7 @@ export type JobType =
   | 'cleanup_seeded_torrents'
   | 'monitor_rss_feeds'
   | 'sync_goodreads_shelves'
+  | 'check_watched_lists'
   | 'send_notification'
   // Ebook-specific job types
   | 'search_ebook'
@@ -113,6 +114,16 @@ export interface SyncGoodreadsShelvesPayload extends JobPayload {
   maxLookupsPerShelf?: number;
 }
 
+export interface CheckWatchedListsPayload extends JobPayload {
+  scheduledJobId?: string;
+  /** If set, only process watched items for this user */
+  userId?: string;
+  /** If set, only process this specific series */
+  seriesAsin?: string;
+  /** If set, only process this specific author */
+  authorAsin?: string;
+}
+
 // Ebook-specific payload interfaces
 export interface SearchEbookPayload extends JobPayload {
   requestId: string;
@@ -384,6 +395,12 @@ export class JobQueueService {
       return await processSyncGoodreadsShelves(payloadWithJobId);
     });
 
+    this.queue.process('check_watched_lists', 1, async (job: BullJob<CheckWatchedListsPayload>) => {
+      const { processCheckWatchedLists } = await import('../processors/check-watched-lists.processor');
+      const payloadWithJobId = await this.ensureJobRecord(job, 'check_watched_lists');
+      return await processCheckWatchedLists(payloadWithJobId);
+    });
+
     // Send notification processor
     this.queue.process('send_notification', 2, async (job: BullJob<SendNotificationPayload>) => {
       const { processSendNotification } = await import('../processors/send-notification.processor');
@@ -766,6 +783,39 @@ export class JobQueueService {
     );
   }
 
+  /**
+   * Add check watched lists job (watched series + watched authors)
+   */
+  async addCheckWatchedListsJob(scheduledJobId?: string): Promise<string> {
+    return await this.addJob(
+      'check_watched_lists',
+      {
+        scheduledJobId,
+      } as CheckWatchedListsPayload,
+      {
+        priority: 7,
+      }
+    );
+  }
+
+  /**
+   * Add a targeted check for a specific watched series or author for a specific user.
+   * Used for immediate processing when a user adds a new watch.
+   */
+  async addCheckWatchedItemJob(userId: string, seriesAsin?: string, authorAsin?: string): Promise<string> {
+    return await this.addJob(
+      'check_watched_lists',
+      {
+        userId,
+        seriesAsin,
+        authorAsin,
+      } as CheckWatchedListsPayload,
+      {
+        priority: 8, // Higher than scheduled (7) since user-initiated
+      }
+    );
+  }
+
   // =========================================================================
   // EBOOK-SPECIFIC JOB METHODS
   // =========================================================================