chore(svc-storage-nfs-server): capture ganesha's NFSv4 verdicts in debug runs

On ubuntu-26.04 runners the swarm deploy fails at svc-storage-nfs-client's
probe-write, right after a successful probe-mount, on every client node:
`Destination directory /run/svc-storage-nfs-client/probe does not exist`.
The rescue bundles cannot say why: ganesha writes to
/var/log/ganesha/ganesha.log, which the swarm diagnostics never collected,
and its NFS_V4 component logged nothing below EVENT.

Debug runs now log NFS_V4 at DEBUG, and the diagnostics append the tail
of ganesha.log to the nfs-boundary section.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

roles/svc-storage-nfs-server/templates/ganesha.conf.j2

@@ -4,6 +4,7 @@ LOG {
     components {
         INIT = FULL_DEBUG;
         DISPATCH = DEBUG;
+        NFS_V4 = DEBUG;
     }
 }
 

scripts/tests/deploy/swarm/utils/collect/diagnostics.sh

@@ -88,6 +88,7 @@ dexec "${NFS_SERVER}" mountpoint "${INFINITO_SWARM_NFS_STATE_PATH:?}" 2>&1
 dexec "${NFS_SERVER}" cat /proc/fs/nfsd/exports 2>&1
 dexec "${NFS_SERVER}" cat /proc/fs/nfsd/versions 2>&1
 dexec "${NFS_SERVER}" sh -c "journalctl -u nfs-server -u nfs-ganesha -u rpcbind --no-pager 2>&1 | tail -50"
+dexec "${NFS_SERVER}" sh -c "tail -n 600 /var/log/ganesha/ganesha.log 2>&1"
 dexec "${NFS_SERVER}" sh -c "command -v ss >/dev/null 2>&1 && { ss -lntp | grep -E ':(2049|111)' || echo '(ss ran: nothing listening on 2049/111)'; } || echo '(ss not installed on this node)'"
 
 sep "ganesha-threads" "nfs-server: ganesha thread states (pins where a wedged startup blocks)"