26.07.01: feat: publish multi-arch docker manifests per distro

Push per-arch images into a single repo with an arch tag suffix
(syncloud/platform-<distro>:<tag>-<arch>) instead of arch-in-repo-name
(syncloud/platform-<distro>-<arch>:<tag>), then fuse them into a
manifest list syncloud/platform-<distro>:<tag> via plugins/manifest.

Consumers can reference syncloud/platform-<distro>:<tag> without the
arch; Docker resolves the right arch per node. Old versions keep the
arch-in-repo-name layout and are untouched; each consumer switches to
the bare name when it bumps to a manifest-bearing platform version.

Manifests: platform-buster, platform-bookworm, bootstrap-bookworm.

26.06.01: fix: buster install without apt; tolerate removed getty unit

install-buster.sh skips 'apt install curl' (curl is already in the
pinned base image, and buster apt repos are EOL).

Dockerfile.platform now uses 'rm -f' on getty@.service so it works
when the unit was already removed in a previous platform image
(buster refresh case).

26.04.10: fix: buster install without apt; tolerate removed getty unit

install-buster.sh skips 'apt install curl' (curl is already in the
pinned base image, and buster apt repos are EOL).

Dockerfile.platform now uses 'rm -f' on getty@.service so it works
when the unit was already removed in a previous platform image
(buster refresh case).

26.04.9

Rebuild platform image after platform 2721 (cli cert --fake) hit stab…

26.04.8

Trigger platform image rebuild to pick up platform commit d4a09fbe (p…

26.04.7: fix: eval rauc shell output instead of stripping quotes

rauc status --output-format=shell emits values single-quoted
(RAUC_SYSTEM_COMPATIBLE='syncloud-amd64-uefi'). Stripping only double
quotes left literal single quotes around the value, producing URLs
like /os/'syncloud-amd64-uefi'/latest.json which 404. Eval handles
all shell quoting correctly.

26.04.6: fix: eval rauc shell output instead of stripping quotes

rauc status --output-format=shell emits values single-quoted
(RAUC_SYSTEM_COMPATIBLE='syncloud-amd64-uefi'). Stripping only double
quotes left literal single quotes around the value, producing URLs
like /os/'syncloud-amd64-uefi'/latest.json which 404. Eval handles
all shell quoting correctly.

26.04.5

feat: support /etc/default/syncloud-update override and /os/ URL name…

26.04.4: fix: install rauc-service package alongside rauc

Debian splits rauc into 'rauc' (CLI) and 'rauc-service' (daemon,
systemd unit, D-Bus activation). Without rauc-service, 'rauc install'
and 'rauc status' fail with 'name de.pengutronix.rauc was not
provided by any .service files'.

26.04.3: feat: pre-install v2 (RAUC A/B update) services, masked by default

Install rauc, data-init, update-agent, and boot-ok services into the
rootfs. All v2 services are masked so v1 images are unaffected.
image-v2 unmasks them and writes board-specific RAUC config during
image assembly.

Unit files go to /usr/lib/systemd/system/, masks (symlinks to
/dev/null) go to /etc/systemd/system/ which takes precedence.