Use quote-sats from btcdata instead of local EUR/BTC calculation

Sats value now comes from btcdata's Strike quote endpoint which
includes the actual fee/spread, matching the Strike app.

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

src/clj/pmagnus/btcprice/web/routes/ws_proxy.clj

@@ -117,16 +117,9 @@
         amount))
     "\u2014"))
 
-(def ^:private sats-eur-amount
-  (double (bigdec (or (System/getenv "SATS_EUR_AMOUNT") "54.46"))))
-
-(defn- eur-to-sats [rates]
-  (when-let [eur-btc (get rates "EUR/BTC")]
-    (long (* sats-eur-amount (double (bigdec eur-btc)) 100000000))))
-
 (defn- strike-json->html [text]
   (let [rates (json/read-str text)
-        sats  (eur-to-sats rates)]
+        sats  (get rates "quote-sats")]
     (str "<div id=\"strike-display\">"
          "<div class=\"rounded-2xl shadow-sm border border-gray-200 p-6\" style=\"background:#f3f4f6;\">"
          (if sats