fix(jellyfinlogin): use externalHostname if set for forgetpassword link

Implemented dynamic URL generation for the 'Forgot Password' feature. If jellyfin external hostname
is set, the URL is generated based on it; otherwise, jellyfin hostname is used as the base URL. The
URL includes additional parameters to handle emby support.

fix #199, fix #424, re #212

server/interfaces/api/settingsInterfaces.ts

@@ -22,6 +22,7 @@ export interface SettingsAboutResponse {
 
 export interface PublicSettingsResponse {
   jellyfinHost?: string;
+  jellyfinExternalHost?: string;
   jellyfinServerName?: string;
   initialized: boolean;
   applicationTitle: string;