Adversarial review of A.0 found two silent-wrong defects reachable via the public
atomic_load/atomic_store intrinsics (raw LLVM verifier errors, not clean sx
diagnostics) + a latent alignment fallback. All fixed:
- scalar-kind allowlist (call.zig): the size-only T guard admitted same-sized
aggregates ([8]u8, 8-byte structs) -> invalid 'load atomic [8 x i8]'. Now an
allowlist switch (integer/float/bool/pointer/enum/vector) rejects loudly.
- per-op ordering validity (call.zig): load cannot release/acq_rel, store cannot
acquire/acq_rel -> loud diagnostic instead of invalid LLVM.
- val_ty align fallback (ops.zig): the 'else .i64' (align 8) default would
over-align a sub-8 store -> now bails loudly on a missing val_ty.
Locked by examples 1130 (non-scalar) + 1131 (bad ordering). Suite green (713/0).
