This PR introduces changes to allow installing greenboot RPM packages from a given RHEL compose as an alternative to the default Copr-based install, and extends bootc test coverage to RHEL 9.9 and RHEL 10.3.

ci: allow installing greenboot from compose RPMs as an alternative to Copr

Copr remains the default source for greenboot builds in the qcow2, anaconda-iso, and ostree CI test cases. When both DOWNLOAD_NODE and COMPOSE_ID environment variables are set, these tests instead fetch pre-built greenboot RPMs directly from the RHEL compose available at the DOWNLOAD_NODE URL. This is primarily useful for RHEL targets (9.8, 9.9, 10.2, 10.3), where Copr can only provide a CentOS Stream approximation, and
makes local testing against specific RC or nightly composes simpler and more automated.

The RPM download logic has been extracted into a shared helper (tests/common/download-compose-rpms.sh) to avoid duplication across scripts. The helper fetches the packages index page once and reuses it for both RPM lookups.

ci: add RHEL 9.9 and RHEL 10.3 support to bootc test cases

Extends the bootc qcow2 and anaconda-iso test scripts to support RHEL 9.9 and RHEL 10.3 alongside the existing 9.8 and 10.2 variants. Each new distro gets its own DNF repo file with REPLACE_ME_HERE and REPLACE_ARCH_HERE placeholders substituted at runtime from DOWNLOAD_NODE and the detected architecture, respectively. CI jobs rhel-9-9-bootc and rhel-10-3-bootc are added to greenboot-ci.yaml targeting the corresponding nightly composes.

Note: The ostree test case is not updated yet as RHEL 9.9 support there is not ready.

Local testing (compose RPM mode)

Run each script directly on a host matching the target distro, from inside the tests/ directory.
greenboot-bootc-anaconda-iso.sh

sudo env \
  DOWNLOAD_NODE="download-node.example.com" \
  COMPOSE_ID="RHEL-9.9.0-20260130.0" \
  QUAY_USERNAME="quay-user" \
  QUAY_PASSWORD="quay-password" \
  STAGE_REDHAT_IO_USERNAME="stage-redhat-user" \
  STAGE_REDHAT_IO_TOKEN="stage-redhat-token" \
  ./greenboot-bootc-anaconda-iso.sh

greenboot-bootc-qcow2.sh

sudo env \
  DOWNLOAD_NODE="download-node.example.com" \
  COMPOSE_ID="RHEL-10.3.0-20260130.0" \
  QUAY_USERNAME="quay-user" \
  QUAY_PASSWORD="quay-password" \
  STAGE_REDHAT_IO_USERNAME="stage-redhat-user" \
  STAGE_REDHAT_IO_TOKEN="stage-redhat-token" \
  ./greenboot-bootc-qcow2.sh

greenboot-ostree.sh

sudo env \
  DOWNLOAD_NODE="download-node.example.com" \
  COMPOSE_ID="RHEL-9.9.0-20260130.0" \
  ./greenboot-ostree.sh

Assisted-by: Claude (claude-sonnet-5)