test/changelog.test.sh drives changelog_fragments (order, marker, absent
dir), changelog_fragment_problem (every rule, file named each time), and
changelog_assemble (both shapes, canonical order, mixed-shape refusals).
test/changelog-assemble.test.sh drives the CLI against constructed trees:
exact-byte writes, provably read-only --check, every refusal from the
spec, the publisher/assembler round trip, and idempotence.
Closes#114.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
