feat: add NFS server and Transmission service to sleeper-service

- Created modules/services/nfs.nix for network file sharing
- Updated sleeper-service configuration with NFS and Transmission
- Fixed SSH key management to use direct key configuration
- Updated hardware-configuration to use sleeper-service hostname
- Added firewall ports for Transmission RPC (9091)

modules/services/nfs.nix

@@ -0,0 +1,31 @@
+# NFS Server Configuration
+# Network File System server for home lab storage
+{ config, pkgs, ... }:
+
+{
+  # NFS server configuration
+  services.nfs.server = {
+    enable = true;
+    # Export the storage directory
+    exports = ''
+      /mnt/storage    10.0.0.0/24(rw,sync,no_subtree_check,no_root_squash)
+    '';
+    # Create exports on startup
+    createMountPoints = true;
+  };
+
+  # Ensure the storage directory exists
+  systemd.tmpfiles.rules = [
+    "d /mnt/storage 0755 geir users -"
+    "d /mnt/storage/media 0755 geir users -"
+    "d /mnt/storage/downloads 0755 geir users -"
+    "d /mnt/storage/backups 0755 geir users -"
+  ];
+
+  # Required packages for NFS
+  environment.systemPackages = with pkgs; [
+    nfs-utils
+  ];
+
+  # Firewall rules are already configured in network module
+}