Ban em-dashes outright #28

Parent

#21

What to build

With both rewrite batches merged, the allow list is empty and is deleted. The test becomes a flat ban on em-dashes in tracked text outside docs/mde and CHANGELOG.md, and its failure message says what to use instead. If the rule ledger exists by then, the ban gets its ID and its row there; otherwise the ledger ticket adds them.

Acceptance criteria

• The allow list is gone, and the test no longer reads one.
• Adding an em-dash anywhere outside the two exclusions fails the test.

Blocked by

• Rewrite the em-dashes in the specification #26
• Rewrite the em-dashes in the decision records, registers, root documents and tooling #27