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/app/api/requests/route.ts

@@ -53,7 +53,7 @@ export async function POST(request: NextRequest) {
         narrator: audiobook.narrator,
         description: audiobook.description,
         coverArtUrl: audiobook.coverArtUrl,
-      }, { skipAutoSearch });
+      }, { skipAutoSearch, bypassIgnore: true });
 
       if (!result.success) {
         const statusMap: Record<string, { error: string; status: number }> = {
@@ -61,6 +61,7 @@ export async function POST(request: NextRequest) {
           being_processed: { error: 'BeingProcessed', status: 409 },
           duplicate: { error: 'DuplicateRequest', status: 409 },
           user_not_found: { error: 'UserNotFound', status: 404 },
+          ignored: { error: 'Ignored', status: 409 },
         };
         const mapped = statusMap[result.reason] || { error: 'RequestError', status: 500 };
         return NextResponse.json(