M1 (bug): flag-OFF path now caches under (bucket, '_legacy') instead of
(bucket, None), preventing stale old-table ratio being served when
tier_aware_ratio_enabled is flipped ON without process restart.
M2 (guard): add band-drift comment to migration 098 seed + regression test
asserting _PPM2_MIN==30000 and asking_ratio_ppm2_max default==1_200_000.
M3 (doc): append NOTE(#928) to estimator call-site comment explaining that
tier placement uses the pre-anchor radius median, not the same-building Tukey
anchor; flags the revisit needed before enabling the flag in production.
bot-backend
4b0fd10cb0