Add ASIN support to file organization and metadata

This update enhances audiobook file organization by including the ASIN in folder names and embedding it as a custom metadata tag in audio files (M4B/M4A/MP3). Documentation is updated to reflect the new folder naming convention and metadata tagging. Additionally, local login and registration can now be disabled via an environment variable, and the interactive torrent search modal allows custom search titles for all modes.

src/app/login/page.tsx

@@ -37,6 +37,7 @@ function LoginContent() {
     registrationEnabled: boolean;
     hasLocalUsers: boolean;
     oidcProviderName: string | null;
+    localLoginDisabled: boolean;
   } | null>(null);
   const [showRegisterForm, setShowRegisterForm] = useState(false);
   const [registerUsername, setRegisterUsername] = useState('');
@@ -75,6 +76,7 @@ function LoginContent() {
           registrationEnabled: false,
           hasLocalUsers: false,
           oidcProviderName: null,
+          localLoginDisabled: false,
         });
       }
     };
@@ -727,7 +729,7 @@ function LoginContent() {
                 )}
 
                 {/* Admin Login toggle for Plex mode */}
-                {authProviders.providers.includes('plex') && !authProviders.providers.includes('local') && (
+                {authProviders.providers.includes('plex') && !authProviders.providers.includes('local') && !authProviders.localLoginDisabled && (
                   <>
                     <div className="relative my-6 sm:my-8">
                       <div className="absolute inset-0 flex items-center">