Add Strike quote endpoint for real sats price with fee-adjusted amount

Use POST /v1/currency-exchange-quotes to get actual buy price including
spread, matching the Strike app. Fee is cached daily to calculate the
pre-fee amount from the configured total (default 55 EUR). Store
quote_sats in the strike_price DB table.

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

resources/queries.sql

@@ -45,7 +45,7 @@ SELECT ts FROM kraken_day ORDER BY ts DESC LIMIT 1
 
 -- :name insert-strike-price! :! :n
 -- :doc Insert a Strike ticker snapshot
-INSERT INTO strike_price (rates) VALUES (:rates)
+INSERT INTO strike_price (rates, quote_sats) VALUES (:rates, :quote-sats)
 
 -- :name get-latest-strike-price :? :1
 -- :doc Get the most recent Strike ticker snapshot