[Bug] JMD Currency Precision — Backend

[islandbitcoin]

JMD Currency Precision — Backend Fixes

Root cause: Multiple layers of the price pipeline are broken independently and stack for JMD users.

Checklist

• Transaction history adaptor — hardcoded USD, wrong offset, Math.floor truncates prices to 0, no JMD conversion (Urgent)
• Price service BTC triangulation — should use static JMD/USD rate from config yaml.ts (Urgent)
• me query balance — returns fractional cents incorrectly (Medium)
• sendAll fees — doesn't account for fees (Low)

Fix Order

Fix adaptor and price service first — they are the backend source of truth. Once those land, mobile fixes can be validated against correct backend data.

PR Review: Ben + Dread (islandbitcoin) must approve before merge.

[linear]

ENG-132

[islandbitcoin]

src/app/wallets/get-transactions-for-wallet.ts, lines ~37-50.

That's the adaptor that converts Ibex API responses into the domain transaction format. Four separate bugs in one spot:

• Line ~41: offset: 0n (should be SAT_PRICE_PRECISION_OFFSET of 12 or USD_PRICE_PRECISION_OFFSET of 6)
• Line ~43: displayCurrency: "USD" hardcoded (ignores user's JMD setting)
• Line ~39: Math.floor(trx.exchangeRateCurrencySats) truncates per-sat prices like 0.00000007 to 0
• Lines ~47-48: settlementDisplayAmount and settlementDisplayFee pass through raw Ibex USD strings, never converted to JMD