How an edge reverse proxy uses fixed-memory sketches to survive infinite-cardinality attacks, credential abuse, and runaway agent loops. In Part 1 , we explored Interpreted Decay — calculating recency-weighted frequency on-the-fly at read time ( count >> age ) in a single 64-bit word. In Part 2 , we looked under the hood at atomic Compare-And-Swap (CAS) state transitions, bit-chipping eviction lotteries, and sub-35ns multi-core scaling. Data structures prove their real value wh...