DC-NODE-46

Every ADMITTED ForgeTick yields either a structured refusal or a leader-schedule decision. No admitted tick may disappear, and none may report a reason that is not its own. (a) TYPED KES WINDOW: the slot's KES evolution index is consumed as a Result -- CoordinatorState::kes_period_for_slot_checked -> KesSlotError{BeforeOperationalCertificateStart, AfterOperationalCertificateEnd, PeriodArithmeticOverflow}, each carrying the SLOT BOUND an operator can act on, routed as ForgeRefused::KesWindow. The if let Some(kes_period) skip that silently consumed the whole forge attempt is removed. (b) ONE DEFINITION: the Option accessor kes_period_for_slot delegates to the checked form, so the two can never disagree about which slots are signable. (c) FAMILIES STAY SEPARABLE: slot-derivation, KES-window (three distinct reasons), tip/fence and leadership failures project to DISTINCT emitted discriminators -- never one collapsed reason. (d) HONEST OUTCOME: an admitted tick that was refused emits ForgeOutcome::Refused with its reason; no_tip_available is narrowed to a genuinely absent tip (it was previously a catch-all that reported a KES refusal while the node held a perfectly good tip). (e) NO STALE REASON: last_forge_refused is cleared on entry to the ForgeTick arm, so a tick with nothing of its own to report says so instead of re-emitting the previous tick's reason and tip operands.