sim-bringup

Bring up a behavioral (RTL) simulation end-to-end: stand up or fix a testbench, compile (xvlog/xvhdl), elaborate (xelab), run (xsim), and methodically diagnose compile errors, elaboration failures, $fatal/assertion failures, X-propagation, and hangs. Use when the user says "simulate this", "run the testbench", "set up simulation", "my sim fails / hangs / shows X", "why does my testbench not pass", "add a testbench…