fix(nutzap): orange highlight on the lightning bolt for cashu zaps

The reaction-row icon turns orange when the logged-in user has
zapped a note. Phase 1 extended Note.isZappedBy to detect cashu
zaps, but ObserveZapIconState had a fast-path gate that skipped
the whole calculation when the note had no LN zap data:

    val hasZapData =
        zapsState?.note?.zapPayments?.isNotEmpty() == true ||
            zapsState?.note?.zaps?.isNotEmpty() == true

A cashu-only zap leaves both `zaps` and `zapPayments` empty, so
hasZapData was false, wasZapped was hard-coded false, and the
new isZappedBy logic never ran. The amount counter still updated
because that path (Note.zapsAmount) was already extended in
Phase 1 — only the icon gate was missing the third source.

Add `nutzaps?.isNotEmpty()` to the gate.

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/note/ReactionsRow.kt

@@ -1457,7 +1457,8 @@ fun ObserveZapIconState(
         LaunchedEffect(key1 = zapsState, key2 = hasPendingPaymentRequest) {
             val hasZapData =
                 zapsState?.note?.zapPayments?.isNotEmpty() == true ||
-                    zapsState?.note?.zaps?.isNotEmpty() == true
+                    zapsState?.note?.zaps?.isNotEmpty() == true ||
+                    zapsState?.note?.nutzaps?.isNotEmpty() == true
             val wasZapped =
                 if (hasZapData) {
                     accountViewModel.calculateIfNoteWasZappedByAccount(baseNote, afterTimeInSeconds)