윤정민
6fc00b2952
waitForCache, the schedule month-poll loop, and getOrFetchDynamic all polled Firestore every fixed 500ms (up to ~50 reads) while waiting for a lock holder to populate the cache. Replace the fixed interval with a shared backoffDelayMs helper (300ms base, doubling, 5s cap) bounded by the same ~25s timeout, cutting per-waiter read amplification by roughly 5x. Timeout/fallback semantics are unchanged.