Introduce BuildOptions to parameterize build and rebuild.
Add build_with_options/rebuild_with_options to support locked, offline, and
require-pinned-image modes. Locked mode verifies an existing lock file and
fails on drift. Offline mode fails fast when system packages are requested.
Also re-export BuildOptions from karapace-core.
- Run cargo fmt on skip_if_root() blocks
- Add skip_if_root() to migrate_atomic_version_unchanged_on_write_failure
- Add libc dev-dependency to karapace-store for root check
- Remove explicit shell: sh from container rustup steps (OCI exec
can't find sh in PATH; default run shell works)
- Add skip_if_root() to 8 permission-based tests (root bypasses
filesystem permissions in Docker containers)
- Replace dtolnay/rust-toolchain with manual rustup install via sh
for container-based jobs (opensuse lacks bash, which the composite
action requires)
- Keep dtolnay/rust-toolchain for non-container ubuntu jobs