Block plugin routes for share guests (#16)

* block plugin routes for share guests

Adds a global MVC filter that refuses share-guest accounts on any plugin
controller. Jellyfin's own API stays open, the share tag policy already
bounds it and playback needs it.

Guests are identified by the auth provider marker on the account, so this
covers a leaked token used from curl or a native client, not just the web
client where the CSS lockdown runs.

* add plugin exception list and honest wording

Config page lists installed plugins with a checkbox each, for the ones that
need to answer guests during playback. Default is unticked.

Renames the hidden selectors setting to say it is cosmetic, and stops the
readme implying the web client lockdown confines anything.

* bump to 1.0.4.0

Jellyfin.Plugin.ShareLinks/PluginServiceRegistrator.cs

@@ -1,10 +1,12 @@
 using Jellyfin.Plugin.ShareLinks.Lifecycle;
+using Jellyfin.Plugin.ShareLinks.Security;
 using Jellyfin.Plugin.ShareLinks.Services;
 using Jellyfin.Plugin.ShareLinks.Storage;
 using Jellyfin.Plugin.ShareLinks.Web;
 using MediaBrowser.Controller;
 using MediaBrowser.Controller.Authentication;
 using MediaBrowser.Controller.Plugins;
+using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace Jellyfin.Plugin.ShareLinks;
@@ -20,6 +22,12 @@ public class PluginServiceRegistrator : IPluginServiceRegistrator
     {
         _ = applicationHost;
 
+        // Registered as a global MVC filter so it sees every plugin's controllers,
+        // not just this one's. Options are materialised after all plugin registrators
+        // have run, so adding to the collection here is in time.
+        serviceCollection.AddSingleton<GuestPluginApiGuard>();
+        serviceCollection.Configure<MvcOptions>(options => options.Filters.AddService<GuestPluginApiGuard>());
+
         serviceCollection.AddHostedService<WebInjectionHostedService>();
         serviceCollection.AddSingleton<ShareLinkStore>();
         serviceCollection.AddSingleton<ShareTokenService>();