mount nas shares on demand

modules/hosts/shadow/disks.nix

@@ -53,6 +53,22 @@
         "x-systemd.device-timeout=10"
       ];
     };
+
+    # Pin the NFS server until nas.hfx.ahmza.com points at 10.10.100.4.
+    # Automounting keeps an unavailable NAS out of the boot path.
+    nfsShare = export: {
+      device = "10.10.100.4:${export}";
+      fsType = "nfs";
+      options = [
+        "nfsvers=4.2"
+        "noauto"
+        "nofail"
+        "_netdev"
+        "x-systemd.automount"
+        "x-systemd.idle-timeout=600"
+        "x-systemd.mount-timeout=10"
+      ];
+    };
   in {
     fileSystems = {
       # Boot essentials, by UUID. UUIDs rather than labels here on purpose:
@@ -72,6 +88,8 @@
       "/mnt/dump" = spinningDrive "DUMP";
       "/mnt/bak" = spinningDrive "BAK";
       "/mnt/games" = eagerDrive "GAMES";
+      "/mnt/nas" = nfsShare "/srv/nas";
+      "/mnt/media" = nfsShare "/srv/media";
     };
 
     # Swap exists for hibernation, not for memory pressure — 31GiB of RAM on a