Add deposit totals API endpoint

GET /api/deposits/totals returns fiat deposited per exchange per currency
from bank_to_exchange events, aggregated via SQL.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/queries.sql

@@ -125,6 +125,16 @@ LEFT JOIN wallets tw ON tw.id = e.to_wallet_id
 WHERE e.from_wallet_id = :wallet-id OR e.to_wallet_id = :wallet-id
 ORDER BY e.occurred_at DESC
 
+-- :name get-deposit-totals :? :*
+-- :doc Total fiat deposited per exchange per currency from bank_to_exchange events
+SELECT tw.name AS exchange, e.fiat_currency AS currency,
+       SUM(e.fiat_amount) AS total
+FROM events e
+JOIN wallets tw ON tw.id = e.to_wallet_id
+WHERE e.event_type = 'bank_to_exchange'
+GROUP BY tw.name, e.fiat_currency
+ORDER BY tw.name, e.fiat_currency
+
 -- :name get-wallet-balances :? :*
 -- :doc Compute sats balance per wallet from events
 SELECT w.id, w.name,