Land T2.1i: the case format carries rows_per_call and the failed call

Both reviews approve d8d1651, which the candidate 2bb7d49 is, moved over
landing commits only.

Moved from d8d1651: its run 39170649810
is green at d8d1651 and both reviews
approve it. The candidate 2bb7d49 is
that commit moved over landing commits only (each commit with its
partner's tree in order, only landing commits added), so it lands on
that evidence (E130); this commit changes no file, so the phase branch
moves at once and CI skips its own runs (E43 (b), E131).

Reviewed-by: independent reviewer (fresh agent) and Codex, T2.1i
Protected-paths: contract/case.schema.json; contract/runners/run_python.py; contract/tests/malformed-cases.json; rust/crates/sdm-testkit/src/case.rs
Base-SHA: d339e88
Checkpoint-SHA: d339e88
Moved-from: d8d1651
Moved-from-run: 39170649810
Signed-off-by: Adi Wadaskar <awadaskar@nvidia.com>

Author: adi-kumo