Add e-book sidecar integration and improve request handling

Introduces optional e-book sidecar downloads from Anna's Archive, including admin UI, settings API, FlareSolverr integration, and documentation. Enhances request creation logic to prevent duplicate downloads by checking for 'downloaded' and 'available' statuses, updates UI to reflect processing state, and adds SABnzbd support to download and cleanup flows. Also updates ranking algorithm documentation and improves cache invalidation for recent requests.

src/lib/processors/scan-plex.processor.ts

@@ -373,6 +373,16 @@ export async function processScanPlex(payload: ScanPlexPayload): Promise<any> {
           });
 
           matchedCount++;
+
+          // Trigger metadata match for Audiobookshelf items (only for our downloaded requests)
+          if (backendMode === 'audiobookshelf') {
+            const itemId = match.plexGuid; // plexGuid contains the Audiobookshelf item ID
+            const asin = audiobook.audibleAsin || undefined;
+            const matchInfo = asin ? ` with ASIN ${asin}` : '';
+            await logger?.info(`Triggering metadata match for matched item: ${itemId}${matchInfo}`);
+            const { triggerABSItemMatch } = await import('../services/audiobookshelf/api');
+            await triggerABSItemMatch(itemId, asin);
+          }
         }
       } catch (error) {
         await logger?.error(`Failed to match request ${request.id}: ${error instanceof Error ? error.message : 'Unknown error'}`);