chore: Cargo.toml fixes (#2416)

Author: jonathanpwang

crates/verify-stark/Cargo.toml

@@ -19,5 +19,4 @@ thiserror.workspace = true
 zstd.workspace = true
 
 [features]
-default = ["parallel"]
-parallel = ["openvm-stark-backend/parallel"]
+default = []

crates/vm/src/arch/vm.rs

@@ -1547,12 +1547,9 @@ mod vm_metrics {
             for (pk, height) in zip(&self.pk.per_air, heights.iter()) {
                 let width = &pk.vk.params.width;
                 main_cells_used += width.main_width() * *height;
-                total_cells_used +=
-                    width.total_width(
-                        <<E::SC as StarkProtocolConfig>::Challenge as BasedVectorSpace<
-                            Val<E::SC>,
-                        >>::DIMENSION,
-                    ) * *height;
+                total_cells_used += width.total_width(
+                    <<E::SC as StarkProtocolConfig>::EF as BasedVectorSpace<Val<E::SC>>>::DIMENSION,
+                ) * *height;
             }
             tracing::debug!(?heights);
             tracing::info!(main_cells_used, total_cells_used);

crates/vm/src/metrics/mod.rs

@@ -8,7 +8,7 @@ use openvm_instructions::{
     exe::{FnBound, FnBounds},
     program::ProgramDebugInfo,
 };
-use openvm_stark_backend::prover::{hal::ProverBackend, types::DeviceMultiStarkProvingKey};
+use openvm_stark_backend::prover::{DeviceMultiStarkProvingKey, ProverBackend};
 
 use crate::{
     arch::{