[diegosouzapw]

Closes #4438

Problem

The quota cache background refresh ticks every 60s and setQuotaCache persisted a quota_snapshots row for every window of every connection regardless of whether the value changed. With 273 connections (83 idle), this generated 400K–545K rows/day of near-duplicate data.

Fix

setQuotaCache now captures the prior cache entry before overwriting and gates each saveQuotaSnapshot call through a new pure helper quotaSnapshotChanged(prior, windowKey, remainingPercentage, exhausted):

• writes when there is no prior entry (first observation / baseline row)
• writes when the window was never seen before
• writes on any real change to remaining_percentage or is_exhausted
• skips when both are unchanged (idle connection no-op refresh)

Trend/time-series data is preserved (every change still lands a row); only redundant idle rows are dropped.

Test (Hard Rule #18 — TDD)

New tests/unit/quota-cache-snapshot-dedup-4438.test.ts (5 cases). Confirmed RED before the helper existed → GREEN after (5/5). typecheck:core clean, eslint clean on touched files.

Scope

Surgical: src/domain/quotaCache.ts (pure helper + one gate) + test + CHANGELOG. No schema/migration change; batching/lastActivityAt left as a follow-up.

[gemini-code-assist]

Warning

You have reached your daily quota limit. Please wait up to 24 hours and I will start processing your requests again!

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.