Remove Verilator batch simulation mode

[daiyongyuan]

Summary

• remove the run verilator --batch CLI option
• stop forwarding +batch to the RTL simulator
• remove the batch field from the Verilator run configuration

Verification

• cargo check --locked
• confirmed bebop run verilator --help no longer lists --batch
• feature build was attempted but requires VSRC_PATH and RISCV from the Nix development environment