nx_ladder_gate.nx

nx_ladder_gate.nx -- GATE for the ladder ruler (nx_ladder_lib), driven IN-PROCESS on planted plan rows: a fully declared ladder (two dated targets, every rung placed, every role counted), a plan with rungs but no targets (NO-LADDER, labeled not refused), a target whose bar row does not exist (UNDATED), a target with an unknown class, a rung with no rungrole row, a rung with an unknown role, a rungrole row naming an undeclared target, a board with only best-in-class, an orphan rungrole row naming no rung, a target id declared twice, a rung placed twice (a duplicate role, counted apart from orphans), NUL-terminated lines as the ranker hands them over, and a mixed board whose partition must sum. Every fixture asserts its own condition first. license_tier: ORIGINAL No hw writes (Rule 26).