images: add dev variant alongside each canonical image

[reubeno]

Each non-distroless image under base/images/ now ships in two variants:

• canonical (unsuffixed): runtime points at packages.microsoft.com/ azurelinux/4.0/beta and ships azurelinux-repos.
• -dev: runtime points at the daily azl4-dev blob and ships azurelinux-repos-dev.

Variants share a single build-time repository (azl4-dev) and differ only in the runtime -repos package. For the core container the canonical variant tags :4.0 + :latest, while -dev tags :4.0-dev only.

vm-iso-installer threads the variant into config.sh so the offline package bundle and the kickstart %packages section pick up the matching -repos package; the opposite variant is held out of the offline repo to keep the dnf resolver unambiguous at install time.

Distroless containers strip the package manager and have no runtime repo, so they remain single-variant.

[Copilot]

Pull request overview

Adds a -dev image variant alongside most canonical (unsuffixed) Azure Linux images, so the built OS can select its runtime repo source via azurelinux-repos (PMC beta) vs azurelinux-repos-dev (azl4-dev blob), while still sharing a single build-time repo definition.

Changes:

• Register *-dev images in base/images/images.toml and wire them to KIWI profiles.
• Split KIWI definitions into canonical/dev profiles and scope azurelinux-repos* packages per variant (including variant-aware ISO offline repo generation).
• Update static image test routing to treat cases/<family>/ as applying to <family> and <family>-<variant> image names.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
scripts/update-components-list.py	Updates CLI help example path for .packages files to reference the new vm-base-dev output directory.
scripts/demo-build.sh	Switches the demo build to container-base-dev and updates the expected output tar path accordingly.
scripts/common.sh	Updates example VM image path to point at the vm-base-dev output directory.
scripts/build-vm-images.sh	Updates VM image build script to clean/build the vm-base-dev variant.
base/images/wsl/wsl.kiwi	Adds wsl/wsl-dev profiles and scopes azurelinux-repos* selection per variant.
base/images/vm-iso-installer/vm-iso-installer.kiwi	Adds variant profiles and scopes azurelinux-repos* packages per ISO variant.
base/images/vm-iso-installer/config.sh	Detects variant via kiwi_profiles, selects matching repos package, and excludes the opposite variant from the offline repo.
base/images/vm-base/vm-base.kiwi	Adds vm-base/vm-base-dev profiles and scopes azurelinux-repos* packages per variant.
base/images/tests/utils/pytest_plugin.py	Adjusts @pytest.mark.image(...) semantics to match an image family and its -<variant> forms.
base/images/tests/README.md	Documents the canonical vs -dev variant model and updates test selection wording to “image family”.
base/images/images.toml	Registers canonical and -dev entries for VM/container/WSL/installer images (distroless remains single-variant).
base/images/container-base/container-base.kiwi	Adds core-dev profile, scopes runtime azurelinux-repos* per core variant, and sets distinct OCI tags.
.github/instructions/kiwi.instructions.md	Updates KIWI authoring docs to describe canonical + -dev registration via profile.