Add the client script while index.html is served

Writing the tag into index.html on disk fails on most fresh installs
(linuxserver image, distro packages, Docker as a normal user) because
the web files belong to root. A middleware now adds the tag to the
response instead, so the ShareLink action and the guest lockdown work
right after install. The on-disk edit stays as a best-effort extra, and
the tag uses a relative src so it also works under a base URL.

Bump to 1.0.8.0.

Jellyfin.Plugin.ShareLinks/Web/IndexHtmlScriptStartupFilter.cs

@@ -0,0 +1,21 @@
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+
+namespace Jellyfin.Plugin.ShareLinks.Web;
+
+/// <summary>
+/// Puts <see cref="IndexHtmlScriptMiddleware"/> in front of Jellyfin's own pipeline.
+/// </summary>
+public sealed class IndexHtmlScriptStartupFilter : IStartupFilter
+{
+    /// <inheritdoc />
+    public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next)
+    {
+        return app =>
+        {
+            app.UseMiddleware<IndexHtmlScriptMiddleware>();
+            next(app);
+        };
+    }
+}