IntersectMBO

Update CHANGELOG.md files and cabal version numbers for cardano-ledger packages changed since origin/master, following PVP and project RELEASING.md rules. TRIGGER when: about to add, modify, or remove an entry in any `CHANGELOG.md` under this repository; about to bump a `version:` field in any `*.cabal`; user asks to update changelogs, bump versions, or prepare a release/PR; finishing a task that modified Haskell source under `eras/<era>/impl`, `eras/<era>/test-suite`, or `libs/<lib>` (so a changelog entry is likely warranted). SKIP: read-only inspection (no edits planned); only test scenarios changed (no API changes); only value/default changes; user is explicitly hand-editing a CHANGELOG and has not asked the agent to do it; the changed file is in an excluded package per RELEASING.md.