Lookups turned every error into a 404, and region filters into a 400, so a
transient database failure looked final to clients that don't retry 4xx.
Missing rows stay 404/400; anything else is a 500. Empty /regions and
/iatas lists are [] rather than null.
Warn at startup when limits are on without trusted_proxies, and once when a
request carries forwarding headers Beacon ignores. Reject short or whitespace
admin keys and negative durations. Key default-window stats by hour, return
500 for scope lookup failures, and validate IATA path params.
Stats endpoints read hourly rollup tables filled once per closed hour by one
advisory-locked task, instead of materialized views that re-scanned every
observation on each refresh. IATA-set tables give exact distinct counts for any
IATA set or region. Cleanup holds raw rows for unrolled hours (up to 24h).
Adds /stats/series; ingest keeps packet observation counts, observer last IATA,
channel message counts and trace tag summaries. 001_baseline.sql is rewritten,
so pre-release 2.0 databases must be recreated. See docs/historical-stats.md.
MrAlders0n