fix: test_latest_per_keeps_the_latest_sibling flakes on a one-second completion tie #1758

Overview

test_autofit/results/test_identity.py::test_latest_per_keeps_the_latest_sibling failed on main at 963ff296a (Tests run 41456192737, unittest-nojax leg). That failure blocks the release-validation preflight ("PyAutoFit: CI failure").

The test runs two tiny fits of the same search back to back, then expects Aggregator.latest_per() to keep the second. completed_at comes from the status record's updated stamp, which has one-second resolution (%Y-%m-%dT%H:%M:%SZ, autofit/non_linear/status/record.py::_now). When both fits finish within the same second they tie, and latest_per breaks the tie by the greater path, which is an identifier hash. So the test passes or fails by chance. It failed 1 of the last 15 Tests runs.

That tie behaviour is correct: it's deterministic, and real reruns are minutes apart. The bug is in the test.

Plan

• Test-only fix: after the three fits, rewrite the first fit's <output_path>.status.json updated to one minute earlier, so the second fit is unambiguously the later sibling whatever the clock does.
• No library change.

Tier: judge — merge mode: human /prm (corrective PR: unblocks release validate)

Original Prompt