Remove mariner2 (CBL-Mariner 2) support

[cpuguy83]

Mariner 2 has reached end of life. This removes the mariner2 build target, tests, CI configuration, and all documentation references. Tests and configs that referenced mariner2 as a secondary target now use azlinux3 instead.

[Copilot]

Pull request overview

Removes end-of-life Mariner2 (CBL-Mariner 2) target support across the Dalec build system by deleting the target implementation and updating documentation, tests, and CI/bake matrices to use azlinux3 instead.

Changes:

• Remove Mariner2 target registration/config and delete the Mariner2 azlinux RPM target implementation.
• Update docs/examples to replace mariner2/* target references with azlinux3/*.
• Update integration tests and CI/build matrices to stop running/building Mariner2 targets.

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
website/docs/verifying-images.md	Switch example build targets from mariner2/rpm to azlinux3/rpm.
website/docs/targets.md	Remove Mariner2 from target list and update examples/build-context docs to azlinux3.
website/docs/spec.md	Remove Mariner2 examples and references; update base image example to Azure Linux 3.
website/docs/sources.md	Remove Mariner2 mention from target-variant behavior description.
website/docs/signing.md	Update signing examples and supported target list to use azlinux3/rpm.
website/docs/examples/targets.md	Remove Mariner2 target examples from the targets example list.
website/docs/developers.md	Remove Mariner2 integration test suite mention from developer docs.
website/docs/architecture.md	Update BuildMux routing example from mariner2/container to azlinux3/container.
test/windows_test.go	Update build target used in zipper test helper to azlinux3/container.
test/target_azlinux_test.go	Remove TestMariner2 integration test suite.
test/multiple_artifacts_test.go	Change secondary target selection from mariner2 to azlinux3 (with fallback).
test/linux_target_test.go	Remove mariner2 from target map used in tests.
test/fixtures/moby-runc.yml	Remove mariner2 stanza from test fixture targets.
test/fixtures/env-multiple-commands.yml	Remove mariner2-specific target fixture section.
targets/plugin/init.go	Stop registering Mariner2 build target.
targets/linux/rpm/azlinux/mariner2.go	Delete Mariner2 azlinux RPM target config/constants.
targets/linux/rpm/azlinux/common.go	Remove Mariner2 from azlinux target handler map.
targets/linux/distro_handler.go	Update doc comment examples to remove Mariner2.
target.go	Update comment example list to remove Mariner2.
frontend/mux.go	Update comment example routing target from Mariner2 to azlinux3.
docker-bake.hcl	Remove Mariner2 from bake matrices; retarget remaining builds to azlinux3.
.github/workflows/worker-images/matrix.json	Remove mariner2/worker from worker build matrix.
.github/workflows/ci.yml	Remove Mariner2 suite from CI matrix; update docs build example targets to azlinux3.
.github/copilot-instructions.md	Update integration test guidance from TestMariner2 to TestAzlinux3.

[Copilot]

Pull request overview

Removes the end-of-life mariner2 (CBL-Mariner 2) target from Dalec and shifts remaining references/tests/CI examples to use azlinux3, keeping the supported-target surface area consistent across code, docs, and automation.

Changes:

• Removed the mariner2 target implementation/registration and associated test suite coverage.
• Updated docs, fixtures, and examples to reference azlinux3 instead of mariner2.
• Updated CI/build automation matrices (GitHub Actions + docker-bake.hcl) to stop building/testing mariner2 targets.

Reviewed changes

Copilot reviewed 26 out of 26 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
website/docs/verifying-images.md	Updates example build targets to azlinux3/rpm.
website/docs/targets.md	Removes mariner2 from target list and updates examples/context names to azlinux3.
website/docs/spec.md	Removes mariner2 mention/examples; updates base image example to Azure Linux 3.
website/docs/sources.md	Replaces mariner2 mention in target examples.
website/docs/signing.md	Updates signing examples/wording from mariner2 to azlinux3.
website/docs/image.md	Updates base image example to avoid mariner2 reference.
website/docs/examples/targets.md	Removes mariner2 targets from rendered target listing.
website/docs/developers.md	Removes Mariner2 from documented integration test suites.
website/docs/architecture.md	Updates BuildMux routing example to azlinux3/container.
test/windows_test.go	Switches helper build target from mariner2/container to azlinux3/container.
test/target_azlinux_test.go	Removes TestMariner2 integration suite.
test/multiple_artifacts_test.go	Replaces mariner2 secondary target selection with azlinux3 (and fallback).
test/linux_target_test.go	Removes mariner2 from a target mapping used by tests.
test/fixtures/moby-runc.yml	Drops mariner2 target stanza; adds DALEC_TARGET usage for azlinux3-specific behavior.
test/fixtures/env-multiple-commands.yml	Removes mariner2 target stanza from fixture.
targets/plugin/init.go	Stops registering the mariner2 build target.
targets/linux/rpm/azlinux/mariner2.go	Deletes mariner2 distro config/constants.
targets/linux/rpm/azlinux/common.go	Removes mariner2 handler from azlinux target map.
targets/linux/distro_handler.go	Removes mariner2 from doc comment examples.
target.go	Removes mariner2 from doc comment examples.
frontend/mux.go	Updates doc comment example routing target from mariner2 to azlinux3.
docker-bake.hcl	Removes mariner2 from build/test matrices; retargets remaining azlinux builds.
.github/workflows/worker-images/matrix.json	Removes mariner2 worker image from published worker matrix.
.github/workflows/retag/images.yml	Removes mariner2 base image retagging entry.
.github/workflows/ci.yml	Removes Mariner2 from CI integration suite matrix; updates docs build targets to azlinux3.
.github/copilot-instructions.md	Updates instructions to reference TestAzlinux3 and removes Mariner2 mentions.