Round-2 follow-up: profile at 500c/u showed _execute still dominating
the uncached read endpoints (/bounty 76%, /logs/histogram 73%,
/deckies 56%). Same router-level TTL pattern as /stats — 5s window,
asyncio.Lock to collapse concurrent calls into one DB hit.
- /bounty: cache default unfiltered page (limit=50, offset=0,
bounty_type=None, search=None). Filtered requests bypass.
- /logs/histogram: cache default (interval_minutes=15, no filters).
Filtered / non-default interval requests bypass.
- /deckies: cache full response (endpoint takes no params).
- /config: bump _STATE_TTL from 1.0 to 5.0 — admin writes are rare,
1s was too short for bursts to coalesce at high concurrency.