Dictation cleanup

Checks the shipped cleanup prompt and Codex text generation path on synthetic transcripts. No microphone or audio service is used. Run from evals/ with a configured Codex login:

Use --case <id> --samples 1 for a smoke run. By default the three cases run three times each (nine short model calls). Read review.json against each rubric before opening the answer key. Allow cosmetic punctuation differences; do not accept changed meaning or existing draft text copied into the result. Add cases to cases.ts when an actual cleanup failure exposes a missing behavior.