425c349184
The default IVERILOG and VVP paths were hardcoded to macOS Homebrew locations (/opt/homebrew/bin/iverilog). On Ubuntu CI runners, apt installs iverilog to /usr/bin/, so the Path.exists() check returns False and all Tier 2 Verilog cosim tests are silently skipped. Change defaults to bare command names so the existing which-based fallback at line 57-58 discovers the binary via PATH on any platform.