nx_gate_discover_test.nx

nx_gate_discover_test.nx -- GATE + proof for nx_gate_discover (the dynamic feed for the sovereign gate runner). NO LLM, no .sh: it self-asserts a known answer + sys_exit(0). PROVES, on the real _hdl_build/ directory: (1) DISCOVERY WORKS: scanning _hdl_build/ for *_test.nx finds a plausible, non-empty set of gates (verdict == NX_GD_OK). (2) IT FINDS THE KNOWN GATES: the three named gates from the runner's own enrolled list -- nx_superopt_test.nx, nx_rule_soundness_test.nx, nx_eqsat_membership_proof_test.nx -- are all in the discovered set (nx_gate_discover_find returns >= 0 for each). (3) IT CAN BE THE FEED FOR THE GATE RUNNER: each discovered entry carries a NUL-terminated ABSOLUTE path ending in "_test.nx", i.e. exactly the shape gr_gate(testnx: *u8) consumes. We assert the path of a known gate resolves to the expected absolute path string -- proving the path-join produced a runnable feed, without actually running 16 gates here (that is gr_gate's job; this organ proves the SET + PATHS). (4) FAIL-LOUD ON IMPLAUSIBLE COUNT (verify-before-enroll, negative control): scanning a directory with NO gates returns EMPTY (not OK), and a real scan with the floor enforced refuses any count below NX_GD_PLAUSIBLE_FLOOR. We exercise the floor branch with a deliberately-non-gate directory so the IMPLAUSIBLE/EMPTY path is genuinely taken -- a floor that has never fired on a real low-count input is not a guard. KNOWN ANSWER (FAIL LOUD), one line: "<verdict> <count_ge_floor> <found_superopt> <found_soundness> <found_membership> <path_ok> <neg_empty> <neg_floor_caught>" = "0 1 1 1 1 1 1 1 " run=0 verdict 0 = NX_GD_OK; count_ge_floor 1 = count >= NX_GD_PLAUSIBLE_FLOOR; the three found_* = each known gate present; path_ok 1 = a known gate's absolute path == the expected runner-shape string; neg_empty 1 = scanning a no-gate dir returned EMPTY; neg_floor_caught 1 = enforcing the floor on a no-gate dir returned EMPTY/IMPLAUSIBLE (NOT OK).