Fix NFS shares never mounting on lxc-docker

Two compounding bugs, confirmed live on the running lxc-docker
container (vmid 102 on pve.sweet.home):

1. x-systemd.automount never works inside any Linux container --
   systemd logs "Starting of <unit>.automount unsupported" for every
   share and never mounts them. modules/docker/mount-data.nix and
   modules/raspi/mount-data.nix now key off config.boot.isContainer
   (set true by nixpkgs' proxmox-lxc.nix) to mount eagerly with
   `nofail` there instead, while VM-based docker targets keep automount
   unchanged.

2. The container's Proxmox `features` never included `mount=nfs`, so
   AppArmor blanket-denies the nfs/rpc_pipefs mount syscalls NFS
   needs ("permission denied"). scripts/env.sh's
   PROXMOX_DEFAULT_LXC_FEATURES now includes mount=nfs;nfs4 for future
   lxc-* containers -- the semicolon required quoting the --features
   value in create-proxmox-resource.sh's remote pct-create command,
   since it's sent as a raw string for the remote shell to parse and an
   unquoted `;` would be read as a command separator.

The already-running container needs a matching `pct set --features`
plus a restart to pick this up -- that's an operator step outside this
repo.

modules/raspi/mount-data.nix

@@ -1,4 +1,4 @@
-{ vars, ... }:
+{ config, lib, vars, ... }:
 
 {
   fileSystems.${vars.raspiMountpoint} = {
@@ -9,6 +9,15 @@
       "_netdev"
       "noatime"
 
+      # Explicitly use NFSv4.2 if supported
+      "nfsvers=4.2"
+    ] ++ lib.optionals (!config.boot.isContainer) [
+      # `x-systemd.automount` never works inside a Linux container (LXC
+      # included) -- confirmed live on lxc-docker: systemd logs "Starting
+      # of <unit>.automount unsupported" and never mounts it. `nofail`
+      # above already keeps boot non-blocking there, so plain eager
+      # mounting is fine.
+
       # Don't mount until first access
       "x-systemd.automount"
 
@@ -17,9 +26,6 @@
 
       # Give the Pi/Tailscale a little time to appear
       "x-systemd.device-timeout=10s"
-
-      # Explicitly use NFSv4.2 if supported
-      "nfsvers=4.2"
     ];
   };