Get execution environment usage

Returns recorded execution-environment usage for a billing period or a UTC [start,end) window. Custom windows clip recorded intervals, never prorate daily totals, and estimate a full 30 days from complete UTC accounting days within the selected window after environment creation. Days with pending, stale, missing accounting or missing prices are excluded from both the baseline cost and day count; at least one complete day is required. Recorded history and coverage warnings still include incomplete days. EC2 minimum charges follow the existing ledger. Pipeline minutes are attributed on completion. S3 cache storage uses AWS daily size measurements, not sub-day byte telemetry. S3 cache requests come from the bucket's CloudWatch request metrics in 5-minute periods, from when Ravion turned them on; earlier windows report them as missing cost data. Monthly free allowances are not allocated to custom windows.