# Token rate limit: pre-consume, settle, refill

capacity 10000 tokens per hour
take estimate 1500            -> available 8500
settle: prompt 100 + completion 1000 = 1100 -> available 8900
old rule (refund estimate minus PROMPT tokens only): would have refunded 1400 and left 100 charged

take 500, real total 2000     -> available 6900 (the shortfall is charged, not forgiven)

take 6900                     -> available 0
take 1000                     -> rejected: Token rate limit reached for acme

30 minutes later              -> available 5000 (greedy refill: 10000 per hour)
60 more minutes               -> available 10000 (capped at capacity)
