Keep customer coin balances accurate for engineering

Engineering sees 'coins' tags stay stale after redemptions, causing support confusion. This triggers a decrement to the coins tag on webhook receipt so ops and support see accurate balances.

Overview

Stale coin balances lead to support confusion and extra manual fixes that slow operations. Route redemption webhooks into tag updates so customer credits stay accurate, manual corrections disappear, and ops/support always work from the same reliable balance view.

Notable Features

Extract redemption details from webhook
Decrement coins tag on customer
Log adjustments with audit note