Release v4.157.0

Added

• then no events is executable: it asserts that the action produced no new facts, including everything its reactions appended, and after when append it asserts that no reaction appended anything (part of #433)
• when redelivered <Event> to <Reaction> is executable: the located given event is delivered again to the named reaction only, without appending it again, and the ordinary cascade settles; an unhandled refused invocation stays assertable with then error (part of #433)
• Executable model version 17 carries both forms as thenNoEvents and whenRedelivered members, written only when used; models without them keep their version, bytes and outcomes (part of #433)

Changed

• PLAY0268 now names only reaction refusal branches and $refusal values, which remain syntax-only (part of #433)