fix: Remove agreed_price from price API response

The agreed_price depends on trade direction (buy/sell) and must be
calculated on the frontend. Returning a buy-side-only agreed_price
from the API was misleading and unused.

Frontend already calculates the direction-aware price correctly.

frontend/app/admin/trades/page.tsx

@@ -26,14 +26,56 @@ function formatEur(cents: number): string {
 }
 
 /**
- * Format satoshi amount with thousand separators
+ * Format satoshi amount with styled components
+ * Leading zeros are subtle, main digits are prominent
  */
-function formatSats(sats: number): string {
+function SatsDisplay({ sats }: { sats: number }) {
   const btc = sats / 100_000_000;
   const btcStr = btc.toFixed(8);
   const [whole, decimal] = btcStr.split(".");
-  const grouped = decimal.replace(/(.{2})(.{3})(.{3})/, "$1 $2 $3");
-  return `${whole}.${grouped}`;
+
+  const part1 = decimal.slice(0, 2);
+  const part2 = decimal.slice(2, 5);
+  const part3 = decimal.slice(5, 8);
+
+  const fullDecimal = part1 + part2 + part3;
+  let firstNonZero = fullDecimal.length;
+  for (let i = 0; i < fullDecimal.length; i++) {
+    if (fullDecimal[i] !== "0") {
+      firstNonZero = i;
+      break;
+    }
+  }
+
+  const subtleStyle: React.CSSProperties = {
+    opacity: 0.45,
+    fontWeight: 400,
+  };
+
+  const renderPart = (part: string, startIdx: number) => {
+    return part.split("").map((char, i) => {
+      const globalIdx = startIdx + i;
+      const isSubtle = globalIdx < firstNonZero;
+      return (
+        <span key={globalIdx} style={isSubtle ? subtleStyle : undefined}>
+          {char}
+        </span>
+      );
+    });
+  };
+
+  return (
+    <span style={{ fontFamily: "'DM Mono', monospace" }}>
+      <span style={subtleStyle}>₿</span>
+      <span style={subtleStyle}> {whole}.</span>
+      {renderPart(part1, 0)}
+      <span> </span>
+      {renderPart(part2, 2)}
+      <span> </span>
+      {renderPart(part3, 5)}
+      <span> sats</span>
+    </span>
+  );
 }
 
 /**
@@ -289,7 +331,9 @@ export default function AdminTradesPage() {
                         </span>
                         <span style={styles.amount}>{formatEur(trade.eur_amount)}</span>
                         <span style={styles.arrow}>↔</span>
-                        <span style={styles.satsAmount}>{formatSats(trade.sats_amount)} sats</span>
+                        <span style={styles.satsAmount}>
+                          <SatsDisplay sats={trade.sats_amount} />
+                        </span>
                       </div>
 
                       <div style={styles.rateRow}>