k8s nfs backup: exclude namespaces from scaling, isolate per-run state, harden failure handling

- Add EXCLUDED_NAMESPACES (default kube-system,kube-public,kube-node-lease,default); excluded folders are backed up but never scaled
- Use a per-run state dir via mktemp -d so stale .state files from an earlier run can't leak into restores
- Partial folder-backup failure now exits 0 (only zero successes fails); retention runs even on partial failure
- Remove dead SCALE_TIMEOUT_SECONDS config; document SCALE_WAIT_SECONDS
- Add .gitattributes to keep *.sh at LF
- Extend test harness to 44 passing assertions covering exclusions, per-run state, partial/all-failed/empty scenarios

k8s/examples/automated-nfs-backup.env.example

@@ -4,15 +4,16 @@ BACKUP_PASSWORD=
 KUBECTL_BIN=kubectl
 KUBE_CONTEXT=
 WORKLOAD_KINDS=deployment,statefulset,replicaset,replicationcontroller
+EXCLUDED_NAMESPACES=kube-system,kube-public,kube-node-lease,default
 ARCHIVE_PREFIX=nfs-backup
 ARCHIVE_TS_FORMAT=%Y%m%d_%H%M%S
 SEVENZ_METHOD=lzma2
 SEVENZ_LEVEL=9
 SEVENZ_HEADER_ENCRYPT=on
 SEVENZ_THREADS=on
-SCALE_TIMEOUT_SECONDS=600
 SCALE_RETRY_COUNT=3
 SCALE_RETRY_DELAY_SECONDS=5
+SCALE_WAIT_SECONDS=30
 LOG_LEVEL=info
 TMP_STATE_DIR=/tmp/k8s-nfs-backup
 NOTIFY_SUCCESS_URL=