feat: scaffold Antonym fashion store

Anonymous Bitcoin-only fashion e-commerce with:
- Vue 3 + Tailwind 4 frontend with glassmorphism dark/light design system
- Express 5 + SQLite backend with BTCPay Server integration
- Nostr identity (NIP-07/keypair) for anonymous purchase tracking
- ChaCha20-Poly1305 encrypted shipping addresses
- Admin panel with order/product/stock management
- SVG logo splash animation with clip-path reveal
- 5 seeded products across 4 categories

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/lib/nostr.ts

@@ -0,0 +1,28 @@
+export async function sendDm(recipientPubkey: string, message: string): Promise<void> {
+  const privkeyHex = process.env.NOSTR_PRIVATE_KEY
+  if (!privkeyHex || !recipientPubkey) return
+
+  try {
+    const { finalizeEvent } = await import('nostr-tools/pure')
+    const { encrypt } = await import('nostr-tools/nip04')
+    const privkey = Uint8Array.from(Buffer.from(privkeyHex, 'hex'))
+    const ciphertext = await encrypt(privkey, recipientPubkey, message)
+    const event = finalizeEvent({ kind: 4, created_at: Math.floor(Date.now() / 1000), tags: [['p', recipientPubkey]], content: ciphertext }, privkey)
+    privkey.fill(0)
+
+    const { Relay } = await import('nostr-tools/relay')
+    const relays = ['wss://relay.damus.io', 'wss://nos.lol', 'wss://relay.nostr.band']
+    for (const url of relays) {
+      try { const relay = await Relay.connect(url); await relay.publish(event); relay.close() } catch {}
+    }
+  } catch { console.error('Failed to send Nostr DM') }
+}
+
+export async function notifyOrderConfirmed(pubkey: string, orderId: string, totalSats: number): Promise<void> {
+  await sendDm(pubkey, `Your Antonym order ${orderId} for ${totalSats.toLocaleString()} sats has been confirmed. Track it at: ${process.env.SITE_URL || 'http://localhost:3333'}/order/${orderId}`)
+}
+
+export async function notifyStatusUpdate(pubkey: string, orderId: string, status: string, note?: string): Promise<void> {
+  const noteText = note ? ` — ${note}` : ''
+  await sendDm(pubkey, `Your Antonym order ${orderId} has been updated to: ${status}${noteText}`)
+}