Add remote path mapping for qBittorrent integration

Implements remote-to-local path mapping for qBittorrent downloads, allowing the app to handle differing filesystem paths between qBittorrent and the local environment (e.g., remote seedboxes, Docker). Adds UI controls in admin settings and setup wizard, validates mapping configuration, and applies path transformation in download and import processors. Updates documentation, API routes, and data models to support the new feature. Also improves library scan logic to remove stale records and reset orphaned audiobooks and requests. Increases minimum torrent score threshold from 30 to 50 in search and ranking logic, and exposes torrent source URLs in the admin UI.

src/app/setup/page.tsx

@@ -77,6 +77,9 @@ interface SetupState {
   downloadClientUrl: string;
   downloadClientUsername: string;
   downloadClientPassword: string;
+  remotePathMappingEnabled: boolean;
+  remotePath: string;
+  localPath: string;
   downloadDir: string;
   mediaDir: string;
   metadataTaggingEnabled: boolean;
@@ -142,6 +145,9 @@ export default function SetupWizard() {
     downloadClientUrl: '',
     downloadClientUsername: 'admin',
     downloadClientPassword: '',
+    remotePathMappingEnabled: false,
+    remotePath: '',
+    localPath: '',
     downloadDir: '/downloads',
     mediaDir: '/media/audiobooks',
     metadataTaggingEnabled: true,
@@ -211,6 +217,9 @@ export default function SetupWizard() {
           url: state.downloadClientUrl,
           username: state.downloadClientUsername,
           password: state.downloadClientPassword,
+          remotePathMappingEnabled: state.remotePathMappingEnabled,
+          remotePath: state.remotePath,
+          localPath: state.localPath,
         },
         paths: {
           download_dir: state.downloadDir,
@@ -494,6 +503,9 @@ export default function SetupWizard() {
           downloadClientUrl={state.downloadClientUrl}
           downloadClientUsername={state.downloadClientUsername}
           downloadClientPassword={state.downloadClientPassword}
+          remotePathMappingEnabled={state.remotePathMappingEnabled}
+          remotePath={state.remotePath}
+          localPath={state.localPath}
           onUpdate={updateField}
           onNext={() => goToStep(currentStepNumber + 1)}
           onBack={() => goToStep(currentStepNumber - 1)}