Add per-user ignored audiobooks feature

Introduce a per-user "ignored audiobooks" feature to suppress auto-requests. Changes include:

- Database: add Prisma model IgnoredAudiobook and SQL migration to create ignored_audiobooks table with indexes and FK to users.
- Backend: new API routes to list, add, delete, and check ignored audiobooks (/api/user/ignored-audiobooks, /check/:asin, /:id). Add annotateWithIgnoreStatus utility and integrate it into multiple audiobook list endpoints (popular, new-releases, category, search, authors, series).
- Request creator: add ignore-list check (with sibling-ASIN expansion) and a bypassIgnore option for manual requests; return an 'ignored' reason when blocked.
- Frontend: hooks (useIsIgnored, useToggleIgnore, useIgnoredList) and UI updates — AudiobookCard shows an "Ignored" indicator and AudiobookDetailsModal adds an ignore toggle and propagates local state changes.
- Misc: adjust deduplication duration tolerance (to 5% / min 10 minutes), tweak SWR refresh intervals for shelves/syncing, and small logging/info updates.
- Tests: add unit tests for request-creator ignore logic and update existing tests/mocks to account for ignore annotation; extend prisma test helper with ignoredAudiobook mock.

This commit implements the ignore-list end-to-end (DB, server, client, and tests) so users can ignore specific ASINs and have auto-request flows respect that preference.

src/lib/hooks/useAudiobooks.ts

@@ -33,6 +33,7 @@ export interface Audiobook {
   requestId?: string | null;  // ID of request (if any)
   requestedByUsername?: string | null;  // Username who requested (only if not current user)
   hasReportedIssue?: boolean;  // True if an open issue exists for this audiobook
+  isIgnored?: boolean;  // True if this user has ignored this audiobook from auto-requests
 }
 
 export function useAudiobooks(type: 'popular' | 'new-releases', limit: number = 20, page: number = 1, hideAvailable: boolean = false) {