Add scripts and configuration files for mergerfs setup and testing

- Created backup files for wipefs on specific disk partitions.
- Added db-test script to verify metadata.db file integrity.
- Documented successful mergerfs branch and pool configurations in mfs-good.txt.
- Implemented mfs write test in mfs-test.txt.
- Included mergerfs version and device information in mfs.txt.
- Developed rebuild scripts for mergerfs stages, including verification and filesystem creation.
- Generated stage logs for each rebuild step to track disk and filesystem status.
- Added checks for systemd mount requirements and filesystem verification in stage4.

post-rebuild/rebuild-stage1

@@ -0,0 +1,17 @@
+D4='/dev/disk/by-id/wwn-0x5000c500fde02343'
+D8A='/dev/disk/by-id/wwn-0x5000c500e70446ad'
+D8B='/dev/disk/by-id/wwn-0x5000c500ebf2cd37'
+D6='/dev/disk/by-id/wwn-0x5000c500929c8d02'
+
+OS='/dev/disk/by-id/wwn-0x5000000000000000'
+
+for d in "$D4" "$D8A" "$D8B" "$D6"; do
+  echo "=== $d ==="
+  lsblk -dn -o NAME,SIZE,MODEL,SERIAL "$(readlink -f "$d")"
+done
+
+echo
+echo '=== OS — MUST NOT APPEAR ABOVE ==='
+lsblk -dn -o NAME,SIZE,MODEL,SERIAL "$(readlink -f "$OS")"
+
+