Add complete 511-case testbench package
Begins the PR that fills the public packaging gap from 115 to 511 testbench case roots. This first commit adds one missing case; follow-up commits add the remaining cases in bounded batches. Each case is aligned to the published Phoenix-Bench case universe and includes a deterministic runner. Final null/gold calibration remains a separate release-gate task.
Upload complete and path-verified. This PR expands the public testbench package from 115 to 511 case roots. The PR revision contains every locally expected non-generated testbench file (7,243/7,243; missing=0) and a run_verilator.sh for every one of the 511 aligned cases. Generated Verilator coverage .dat files are intentionally excluded because they are execution outputs, not test inputs, and the Hub rejects them as raw binary commit content. PR revision SHA: 31a562ce16b76f401b69057a98dfc904c355125c. Note: final empty-patch/developer-patch calibration and the known candidate-insensitive harness repairs remain a separate release-gate task; this PR closes the public testbench packaging gap.