Add a gated “Feature Matrix” to Mollusk to run the same fixtures under a baseline and one or more feature-enabled variants, compare results for parity, and report compute unit deltas. It’s off by default (feature flag), includes a simple CLI command (mollusk matrix) with --variant name:b58,b58 syntax, and can emit Markdown/JSON reports with thresholds to flag regressions. This helps validate feature activations quickly without a validator and keeps default users unaffected.