[ci skip] complete NFS CSI migration: complex stacks + platform modules

Migrate remaining multi-volume stacks and all platform modules from
inline NFS volumes to CSI-backed PV/PVC with nfs-truenas StorageClass
(soft,timeo=30,retrans=3 mount options).

Complex stacks: openclaw (4 vols), immich (8 vols), frigate (2 vols),
nextcloud (2 vols + old PV replaced), rybbit (1 vol)

Remaining stacks: affine, ebook2audiobook, f1-stream, osm_routing,
real-estate-crawler

Platform modules: monitoring (prometheus, loki, alertmanager PVs
converted from native NFS to CSI), redis, dbaas, technitium,
headscale, vaultwarden, uptime-kuma, mailserver, infra-maintenance

stacks/platform/modules/monitoring/loki.tf

@@ -24,11 +24,16 @@ resource "kubernetes_persistent_volume" "loki" {
     }
     access_modes = ["ReadWriteOnce"]
     persistent_volume_source {
-      nfs {
-        path   = "/mnt/main/loki/loki"
-        server = var.nfs_server
+      csi {
+        driver        = "nfs.csi.k8s.io"
+        volume_handle = "loki"
+        volume_attributes = {
+          server = var.nfs_server
+          share  = "/mnt/main/loki/loki"
+        }
       }
     }
+    storage_class_name               = "nfs-truenas"
     persistent_volume_reclaim_policy = "Retain"
     volume_mode                      = "Filesystem"
   }