feat(docker): switch NFS mounts to HA cluster storage VIP

Updates mount-data.nix to mount all docker shares from
nfs.storage.home (Pacemaker vip-storage, 192.168.20.229) over docker's
eth1/vmbr2 interface instead of server.sweet.home over the LAN.
Adds haStorageNfsFqdn variable to variables.nix for the storage.home
zone FQDN so mounts survive a future VIP renumber without a rebuild.
Storage root changes from /tank (server ZFS pool) to /srv/ha-data
(HA cluster XFS-over-DRBD). Share subpaths are unchanged.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J8djTWdXVzXZc99iujU6T2

variables.nix

@@ -128,6 +128,7 @@
   haClientCidr = "192.168.20.0/24"; # storage-client subnet — VLAN 20, internal to pve1 only
   haClientPrefixLength = 24; # storage-client subnet prefix length (/24)
   haStorageRoot = "/srv/ha-data"; # XFS-over-DRBD mount point on the Active node
+  haStorageNfsFqdn = "nfs.storage.home"; # NFS VIP FQDN (storage.home zone) — resolves to haServerVip; use this in fileSystems device strings
   haIscsiIqn = "iqn.2026-01.home.sweet:ha-storage";
   # DRBD backing disk — identified by SCSI controller path so it resolves to the
   # correct block device regardless of OS-level naming (sda vs sdb can differ