Task 3.2: single requirements, top-level compounds, alternatives and
members push their path level and record one begin and one end; member
failures record the members not tried, merge failures and skipped
alternatives are separate entries, the chosen alternative or all-failed
is recorded, and each compound attempt's reasons are captured before the
job's stored reason is replaced. Scheduling results are unchanged.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>