Function gemm_program 

pub fn gemm_program(m: usize, n: usize, k: usize) -> String

The canonical LOGOS matmul the recognizer lifts: C(m×n) = A(m×k)·B(k×n) over Seq of Int with the deterministic fills a[p] = (p % 7) - 3, b[p] = (p % 11) - 5, and a Show checksum of C — the same program the spatial locks anchor on (tests/common/spatial.rs), here so a report generator can lower it without depending on a test tree.