Drop runExecutionLoop's redundant prompted parameter

[tobyhede]

Parent

#799. Design record: .scratch/render-execution-unit/spec.md.

What to build

Remove runExecutionLoop's prompted parameter. All seven call sites pass the run's own persisted flag, and core already derives the same value from state internally. The parameter is a way for a caller to disagree with state about a fact state owns.

Prefactor: the new entry seam derives prompted from state, so removing the parameter first keeps that change smaller.

Acceptance criteria

• The parameter is gone and every call site updated.
• prompted is read from run state at the one place that needs it.
• No behaviour change — the loop's prompted handling is unchanged for every existing path.

Blocked by

None — can start immediately.