backwards: Add jellyfin module

hosts/backwards/modules/jellyfin/default.nix

@@ -0,0 +1,30 @@
+{ pkgs, ... }:
+{
+  # 1. enable vaapi on OS-level
+  nixpkgs.config.packageOverrides = pkgs: {
+    vaapiIntel = pkgs.vaapiIntel.override { enableHybridCodec = true; };
+  };
+
+  hardware.opengl = {
+    enable = true;
+    extraPackages = with pkgs; [
+      intel-media-driver
+      intel-vaapi-driver # previously vaapiIntel
+      vaapiVdpau
+      libvdpau-va-gl
+      intel-compute-runtime # OpenCL filter support (hardware tonemapping and subtitle burn-in)
+      vpl-gpu-rt # QSV on 11th gen or newer
+    ];
+  };
+
+  services.jellyfin = {
+    enable = true;
+    openFirewall = true;
+  };
+
+  environment.systemPackages = [
+    pkgs.jellyfin
+    pkgs.jellyfin-web
+    pkgs.jellyfin-ffmpeg
+  ];
+}