DC-NODE-28

No forge across unresolved re-selection (rung-2). Once a peer-origin candidate is classified NeedsForkChoice (DC-NODE-23) in a Participant venue, forging is DISABLED until the fork-choice outcome is either (a) durably applied and reconciled (DC-NODE-25/26) or (b) rejected with durable state unchanged. The forge base is NEVER selected from a stale pre-resolution ChainDb::tip while a decision is pending -- a producer tick that fires during a pending decision fails closed (typed ForgeRefused), never forges on the old local tip. This is a producer race fence DISTINCT from pump_block durable admit, rollback replay, or selector / durable reconciliation, so it carries its own evidence. Prevents stale local authority leaking into block production. Derived tier with a true-tier authority consequence.