Refactor use cases to stay orchestration-only

[fleuronvilik]

Objective

Keep use cases thin: orchestration only, with business logic in Domain and Policy layers.

Scope

• Review inline role checks and decision branches.
• Move business-rule logic to explicit Policy or Domain transitions where appropriate.

Acceptance Criteria

• Use cases primarily coordinate repositories, transactions, and transitions.
• No duplicated rule logic across use cases.
• Tests remain green and include at least one regression case.

Why

This reinforces layered architecture and makes behavior easier to reason about.