photon:5.0 arm64 image is missing /bin/sh

Describe the bug

The current Docker Hub photon:5.0 tag has a linux/arm64/v8 manifest entry, but the selected arm64 image appears to be an empty or incomplete rootfs. The arm64 image has only a 127B layer and does not contain /bin/sh, so any Dockerfile with FROM photon:5.0 and a RUN ... step fails for linux/arm64.

Current photon:5.0 arm64 manifest:

Name:        docker.io/library/photon@sha256:08e212e43f3b58825f351481aa342d1289dfbd4c204bb3c269516166a7ff248d
Platform:    linux/arm64/v8
Total Size:  127B
Layer:       sha256:247361b5f2bc5070b6f199e3acda8cd27dc00a2f948e728db449a857b0d9a1cc (127B)
Created:     2026-06-10T23:40:18Z

The amd64 image under the same tag is normal-sized:

Name:        docker.io/library/photon@sha256:4a96607c4af23d317ad525a9ef0434034938fe7d27da88c3301ad0f31d410d19
Platform:    linux/amd64
Total Size:  19.392MB

Screenshot

Reproduction steps

1. Inspect the current photon:5.0 arm64 image:

regctl manifest get photon:5.0 --platform linux/arm64

2. Try to run a shell from the current arm64 image:

docker run --rm --platform linux/arm64 photon:5.0 /bin/sh -c true

3. Or build any multi-platform Dockerfile with a RUN step:

FROM photon:5.0
RUN true

docker buildx build --platform linux/amd64,linux/arm64 -t test/photon-repro .

Observed error from a downstream GitHub Actions build:

runc run failed: unable to start container process: error during container init: exec: "/bin/sh": stat /bin/sh: no such file or directory
ERROR: failed to build: failed to solve: process "/bin/sh -c ..." did not complete successfully: exit code: 1

Expected behavior

photon:5.0 should resolve to a usable Photon OS rootfs for linux/arm64/v8, including /bin/sh, tdnf, and the expected base OS contents, matching the behavior of previous dated 5.0 tags.

For comparison, photon:5.0-20260214 has valid images for both platforms:

linux/amd64: sha256:76d28dc460748d0621207b38fa4dc1950c21b33604e2ccabb78b46d7fcf1c784, 16.255MB
linux/arm64: sha256:8a79b2b149709fead353929f0c550e3bc4d5c67faeba48b4a85f241bee6ffae9, 15.271MB

Additional context

This broke Harbor's Build Package Workflow while rebuilding goharbor/photon:5.0 from FROM photon:5.0 for linux/amd64,linux/arm64.

Failing downstream job:

https://github.com/goharbor/harbor/actions/runs/27345723805/job/80793734074

Temporary downstream workaround PR pins Harbor's wrapper build to photon:5.0-20260214:

https://github.com/goharbor/harbor/pull/23353

The same Harbor workflow passed on 2026-06-09 before the floating photon:5.0 tag moved. That earlier run resolved photon:5.0 to digest sha256:1c4f1a00f97a3d5276c6a4f6e1fe1e4372e5b5c4107e813030f716666dd2fb5a and pulled a normal 15.27MB arm64 layer.

Start by reproducing the failure with regctl manifest get photon:5.0 --platform linux/arm64 and docker run --rm --platform linux/arm64 photon:5.0 /bin/sh -c true. Compare the floating tag with photon:5.0-20260214 and inspect the image publication path for the arm64 manifest. Done means the tag provides a normal Photon rootfs containing /bin/sh and tdnf, and the multi-platform build succeeds.