R8 doc seeded with the SETTLED, Adversary-fuzzed level ladder + tier->rung translation + results.json schema + invariant flags. Card/screenshot/PR-comment/badge sections stubbed (filled as U1-U5 wire + serve their artifacts). Does not advance past the U0 gate; pure documentation of settled design. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>