truenas deprecation: migrate all non-immich storage to proxmox NFS

- Migrate 7 backup CronJobs to Proxmox host NFS (192.168.1.127)
  (etcd, mysql, postgresql, nextcloud, redis, vaultwarden, plotting-book)
- Migrate headscale backup, ebook2audiobook, osm_routing to Proxmox NFS
- Migrate servarr (lidarr, readarr, soulseek) NFS refs to Proxmox
- Remove 79 orphaned TrueNAS NFS module declarations from 49 stacks
- Delete stacks/platform/modules/ (27 dead module copies, 65MB)
- Update nfs-truenas StorageClass to point to Proxmox (192.168.1.127)
- Remove iscsi DNS record from config.tfvars
- Fix woodpecker persistence config and alertmanager PV

Only Immich (8 PVCs, ~1.4TB) remains on TrueNAS.

stacks/nfs-csi/modules/nfs-csi/main.tf

@@ -87,7 +87,7 @@ resource "kubernetes_storage_class" "nfs_truenas" {
   ]
 
   parameters = {
-    server = var.nfs_server
-    share  = "/mnt/main"
+    server = "192.168.1.127"
+    share  = "/srv/nfs"
   }
 }