RTK realized compression this sweep (154 rewrites across 48 ON trials)
  family  calls  compressed  est-raw   saved
  grep      63    69.5 KB   103.8 KB   34.2 KB
  find      82    61.3 KB    87.6 KB   26.3 KB
  ls        53    29.9 KB    53.3 KB   23.5 KB
  tree      11    12.8 KB    21.3 KB    8.5 KB
  git       18    15.6 KB    21.7 KB    6.1 KB
  cat       53    77.9 KB    77.9 KB    0     (RTK does not wrap cat)
  TOTAL           267 KB     366 KB   ~99 KB = ~25,000 tokens
  = 0.08% of ON input naively; ~1-2% after cache re-read compounding.
  vs per-task path variance of +-30% -> below the noise floor.

Verified path-variance (biggest apparent "wins", NOT RTK compression):
  parallel-tfidf -32%: ON 10 steps vs OFF 16, 0 rtk marks, ~1KB output
  react          -21%: ON 30 steps vs OFF 36, 0 rtk marks, ~5KB output (ON also scored WORSE: 0.0 vs 0.5)
  python-scala   -17%: ON  6 steps vs OFF  7, 0 rtk marks, ~1KB output
