feat(zaps): show zap totals to everyone, not just logged-in users

ZapButton already fetched zap receipts for every visitor but returned null
unless you were logged in, so visitors saw no social proof. Now it renders a
read-only '⚡ <total>' whenever there are zaps (with a zap-count tooltip) and
only requires login to OPEN the zap dialog. No extra network cost — the query
already ran unconditionally.

src/components/ZapButton.tsx

@@ -24,21 +24,44 @@ export function ZapButton({
   const { webln, activeNWC } = useWallet();
 
   // Only fetch data if not provided externally
-  const { totalSats: fetchedTotalSats, isLoading } = useZaps(
+  const { totalSats: fetchedTotalSats, zapCount: fetchedZapCount, isLoading } = useZaps(
     externalZapData ? [] : target ?? [], // Empty array prevents fetching if external data provided
     webln,
     activeNWC
   );
 
-  // Don't show zap button if user is not logged in, is the author, or author has no lightning address
-  if (!user || !target || user.pubkey === target.pubkey || (!author?.metadata?.lud16 && !author?.metadata?.lud06)) {
+  if (!target) {
     return null;
   }
 
   // Use external data if provided, otherwise use fetched data
   const totalSats = externalZapData?.totalSats ?? fetchedTotalSats;
+  const zapCount = externalZapData?.count ?? fetchedZapCount;
   const showLoading = externalZapData?.isLoading || isLoading;
 
+  const hasLightning = !!(author?.metadata?.lud16 || author?.metadata?.lud06);
+  const canZap = !!user && user.pubkey !== target.pubkey && hasLightning;
+
+  /**
+   * Read-only total. Zaps are social proof, so the count is shown to EVERYONE —
+   * logged-out visitors included — not just to people who can zap. This costs
+   * no extra network work: `useZaps` already runs above regardless of login.
+   */
+  if (!canZap) {
+    if (!showCount || showLoading || totalSats <= 0) {
+      return null;
+    }
+    return (
+      <span
+        className={`flex items-center gap-1 ${className}`}
+        title={`${zapCount.toLocaleString()} zap${zapCount === 1 ? '' : 's'}`}
+      >
+        <Zap className="h-4 w-4" />
+        <span className="text-xs">{totalSats.toLocaleString()}</span>
+      </span>
+    );
+  }
+
   return (
     <ZapDialog target={target}>
       <div className={`flex items-center gap-1 ${className}`}>