Try to inject the parent image in slopslopstrap

AGENTS.md

@@ -35,5 +35,8 @@ Do not remove existing instructions unless they are outdated or wrong.
 - Forcing `SLOPTRAP_CONTAINER_ENGINE=sloppodman` inside sloptrap also needs `TMPDIR` under `/workspace`; otherwise its build-context path guard rejects the staged Dockerfile under `/tmp` before you reach the real subuid/subgid problem.
 - If a restarted session still inherits stale read-only `/etc/subuid` and `/etc/subgid` tmpfs mounts, an unprivileged agent cannot repair them in-place (`umount` says `must be superuser to unmount`); both podman and sloppodman stay blocked until the session starts without those mounts.
 - Outer sloptrap launches no longer need `/etc/subuid` or `/etc/subgid` bind mounts: `nested-podman` now disables read-only rootfs and the container entrypoint synthesizes container-local subid files from `/proc/self/{uid,gid}_map` before dropping privileges.
+- Even without stale `/etc/subuid` mounts, recursion still fails if the container-local subid files name `sloptrap` instead of the real dropped user (`sk4nz` here): `podman info --debug` warns `no subuid ranges found for user "sk4nz"` and the first inner build dies in `newuidmap ... write to uid_map failed: Operation not permitted`.
+- In this Debian 13 / podman 5.4.2 environment, exporting `_CONTAINERS_USERNS_CONFIGURED=done` for nested podman moves the failure past `newuidmap`, but the next blockers are inside Buildah: with `BUILDAH_ISOLATION=chroot`, recursive builds fail `cannot set --network other than host with --isolation chroot`; without chroot, `podman build` can segfault in `network.defaultNetworkBackend`.
+- Recursive preload now has a host-side path: the outer launcher saves `$SLOPTRAP_IMAGE_NAME` into capability state and mounts it into the container as `SLOPTRAP_RECURSIVE_PARENT_IMAGE_ARCHIVE=/codex/capabilities/podman/preload/<image>.tar`, and child `build-if-missing` tries `sloppodman load -i` before any inner build. A pre-existing session must be restarted to test that path because it cannot add the new preload mount/env to itself after startup.
 - With stale subid mounts gone, recursive `./sloptrap /workspace` can still fail earlier during the inner image build: `crun` tries to open `/proc/sys/net/ipv4/ping_group_range` and gets `Read-only file system` while creating the build container.
 - In a fragile nested-podman session, `podman system migrate` can make things worse: a state that still answered `podman info` fell back to repeated `newuidmap ... write to uid_map failed: Operation not permitted` failures afterward.