The GateStep docstring said on_reject "controls abort / skip behaviour",
omitting the third value. validate() accepts 'abort', 'skip', or 'retry',
and execute() has a dedicated retry branch (returns PAUSED so the next
resume re-runs the gate) distinct from abort (FAILED) and skip (COMPLETED).
Add 'retry' to the docstring so it matches the same file's validate() and
execute() authority.
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Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>