Squadra 3+ 3.13.1

• Fix. In 3.13.0, recovery points were recorded by absolute path only, so a copy of a registry (a clone, a restore, a backup opened with --root) inherited the original's checkpoints and saves, and storage purge --apply run in the copy could remove them. Every checkpoint, adoption and save now records the root of the registry that made it; elsewhere it is listed as foreign and is never a purge target. Records without a root count only inside their own registry. A regression test removes the original's checkpoint on 3.13.0 and keeps it now.
• Found while compacting a real 7.2 GB registry with 3.13.0: storage adopt registered 7 old checkpoints, and storage compact shared 163,794 of 166,663 files and freed 2.62 GB measured on disk, with a full audit passing afterwards.

Update from 3.13.0 is recommended before running storage purge --apply on a copy of a registry. Python 3.12+ is required; plugins unchanged.

Validation: 2277/2277 tests passed on the exact release commit with the strict parallel runner (no known reds accepted). The fix and the release were read and accepted by a Codex window that did not write them.