progress.current is not validated as non-negative (§8.2.1)

[nficano]

Category: spec-conformance Severity: minor
Location: lib/arcp/job/event_body/progress.rb:7-15
Spec: ARCP v1.1 §8.2.1

What

Spec §8.2.1 states current MUST be a non-negative number (and SHOULD be ≤ total when total is present). Neither Progress.from_h nor JobContext#progress validates this, so a negative current is accepted and emitted.

Evidence

def self.from_h(h)
  h = h.transform_keys(&:to_s)
  new(
    current: h.fetch('current'),
    total: h['total'],
    units: h['units'],
    message: h['message']
  )
end

Proposed fix

Validate current >= 0 (raise INVALID_REQUEST otherwise) and warn/guard when total is present and current > total.

Acceptance criteria

• Constructing a progress body with a negative current is rejected.