=== weaviate-0001: RBAC filter O(N*K) -> O(N+K) ===

               scale    defective      fixed    speedup
-------------------------------------------------------
  N= 1000 K= 200       7.66ms     0.09ms     87.5x
  N= 5000 K= 500     112.49ms     0.41ms    277.1x
  N=10000 K=1000     476.87ms     1.07ms    446.3x
  N=20000 K=2000    1590.53ms     1.76ms    906.0x
  N=50000 K=5000    8178.22ms     4.71ms   1735.3x

Conclusion: O(N*K) -> O(N+K) — set hoist is a one-line fix.
At N=50k K=5k, real-world scale, speedup is 100x+.
