ae240140c4
Re-types the engine's ingestion input from a materialized Vec<Vec<(Timestamp, Scalar)>> into a `Source` producer trait the k-way merge drives by peek/next, and proves it against a real, lazily-streamed data-server window in the same cycle — closing the cycle-0011 deliberate eager-materialization gap (C12 Arc<[T]> cross-sim sharing). A VecSource adapter keeps every existing run call site byte-identical (behaviour-preserving); an M1FieldSource streams data-server chunks with O(one-chunk) residency, independent of window length. Foundational cycle of the World-II milestone; #66/#68/#69 inherit the seam. Signed under the boss auto-sign gate: precondition clean, grounding PASS on the final bytes, unanimous five-lens spec-skeptic panel (two editorial ambiguity rounds on the residency predicate repaired to a measured per-pull CHUNK_SIZE ceiling). refs #71