All style regression tests passed on first run — promote them from
optional (continue-on-error) to required. Rebalanced into 4 style
shards + 1 fast shard, all gated by the summary job.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Port the regression test infrastructure from the internal repo to OSS.
Runs golden-baseline visual/audio comparisons inside Docker for deterministic results.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>