- fetchZapCount(eventId): fetches kind 9735 receipts for an event,
parses millisat amounts from embedded zap request description tags,
returns { count, totalSats }
- useZapCount hook: session-cached, same pattern as useReactionCount
- NoteCard: zap button shows "⚡ N sats" when total > 0, falls back
to "⚡ zap" when no zaps yet; stats row shown for logged-out users
displaying ♥ and ⚡ counts when non-zero
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
