Use proper DHV syntax for host volumes

Volumes are now registered as dynamic host volumes via nomad volume register,
not as static host_volume blocks in nomad.hcl. Use access_mode and
attachment_mode in volume stanzas to match DHV API.

frigate.nomad

@@ -21,15 +21,19 @@ job "frigate" {
     }
 
     volume "frigate-config" {
-      type      = "host"
-      source    = "frigate-config"
-      read_only = false
+      type            = "host"
+      source          = "frigate-config"
+      read_only       = false
+      access_mode     = "single-node-writer"
+      attachment_mode = "file-system"
     }
 
     volume "frigate-media" {
-      type      = "host"
-      source    = "frigate-media"
-      read_only = false
+      type            = "host"
+      source          = "frigate-media"
+      read_only       = false
+      access_mode     = "single-node-writer"
+      attachment_mode = "file-system"
     }
 
     task "frigate" {