Phase 1 Gate v0.3

The concluding document of the v0.3 series, formally converging the discoveries accumulated in Documents 12-16 into a four-layer regression protocol. Layer A: the current 12 positive base fixtures must PASS. Layer B: the 13 historical removed fixtures only present in the old version must explicitly FAIL on the converged predicate map from Document 15—weak determinations like just returning "not in final output" are no longer allowed. Layer C: the 4 official discrepancy corpus curves established in Document 09 must continue to be rejected for theorem-level reasons. Layer D: the newly added Algorithm 2 semantic unit tests from Document 16—TWIST_GCD_3N, TWIST_DISC_VAL_GATE_REMOVED—must be tested directly even if the outputs of the 12 positive twists are completely unchanged; they cannot be skipped just because the final output hasn't changed. The document gathers the purpose of the entire v0.3 series into the final 500K Gate rule: only if A+B+C+D all pass is the final 500K result allowed to be marked REPRODUCTION-QUALIFIED; otherwise, no matter how close the final numbers are to the official results, it can at most be marked OUTPUT-MATCHED—the document explicitly emphasizes that these two labels must not be mixed up; "the result numbers happen to be the same" and "reproduced the official criterion logic" are two different things.