Add the DESIGN.md (spec copy + implementation deviations), the trials package
(Trial base + ordered registry + six stress trials: entity swarm, animation
storm, grid titan, pathfinder rush, ui avalanche, sightline siege), and the
RampController/scoring logic. All pure Python under tests/benchmarks/gauntlet/.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
