Define moderation, calibration, and consistency workflows

Design cohort-level tools that help assessment teams compare interpretations and improve consistency without automating academic judgement.

### Deliverables
- Marker calibration workflow
- Moderation and sampling workflow
- Consistency signals and appropriate escalation paths

### Done when
The workflow supports accountable review across markers, submissions, and cohorts.

No files, tests, or entry points are named in the issue. Start by mapping the three listed deliverables—calibration, moderation and sampling, and consistency signals—to the existing assessment-team workflows, then define accountable review boundaries and escalation paths. Done means the workflow supports review across markers, submissions, and cohorts without automating academic judgement.

Written by the indexing model from the issue text.