DC-NODE-05

Forge-slot discipline on the --mode node relay run-loop. A forge is attempted at most once per SlotNo and never for a slot <= the last forged slot (no past or duplicate forge). The current slot is derived ONLY through the clock seam: RED observes wall-clock (SystemClock), GREEN converts via millis_to_slot over the SystemStart anchor + EraSchedule slot length -- only SlotNo crosses the seam (no SystemTime/Instant/float past the RED observation boundary). The forge tick advances NO durable tip and admits/serves/gossips nothing -- it is subordinate to the sync spine, whose run_node_sync -> pump_block path remains the sole durable tip-advance authority; a forged block is a local self-accept artifact only. For a fixed recovered state, ordered block feed, injected clock tick schedule, and shutdown schedule, the forge-attempt sequence and forged block bytes are byte-identical across runs (replay-equivalent). Leadership eligibility is NOT decided in the loop or the GREEN planner (whose forge input is a content-blind Due|NotDue) -- it stays in BLUE inside forge_one_from_recovered. Single-epoch this cluster: an unsupported slot fails closed / skips with a structured local outcome (cluster-scope containment, not permanent behavior).