Implement r5500 media stack configuration with NFS and Docker services

- Added configuration for media stack on r5500, including paths for Jellyfin, Sonarr, Radarr, and other media services.
- Integrated NFS client for accessing Jellyfin libraries from nixdesk.
- Established Docker services for Dispatcharr and Organizr, including necessary user and group setups.
- Created systemd services for managing media directories and ensuring proper permissions.

modules/hosts/r5500/_services/nixdesk-nfs-client.nix

@@ -0,0 +1,28 @@
+# NFS mounts of nixdesk (14900k) bulk storage for r5500. Exports live in
+#   modules/hosts/14900k/_private/jellyfin-nfs-export.nix
+#
+# Jellyfin library paths:
+#   Movies → /mnt/nixdesk-jellyfin/movies
+#   Shows  → /mnt/nixdesk-jellyfin/tv
+{ ... }:
+let
+  nfsExportHost = "192.168.2.25";
+  nfsClientOpts = [
+    "rw"
+    "noatime"
+    "nofail"
+    "_netdev"
+    "nfsvers=3"
+    "tcp"
+    "lookupcache=none"
+    "x-systemd.automount"
+    "x-systemd.idle-timeout=3600"
+  ];
+in
+{
+  fileSystems."/mnt/nixdesk-jellyfin" = {
+    device = "${nfsExportHost}:/mnt/deep/jellyfin";
+    fsType = "nfs";
+    options = nfsClientOpts;
+  };
+}