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>

env.example.txt

@@ -0,0 +1,24 @@
+# BTCPay Server
+BTCPAY_URL=https://btcpay.example.com
+BTCPAY_API_KEY=
+BTCPAY_STORE_ID=
+BTCPAY_WEBHOOK_SECRET=
+
+# Encryption (32-byte hex string for ChaCha20-Poly1305)
+ENCRYPTION_KEY=
+
+# Admin
+ADMIN_PASSWORD=
+
+# SMTP (optional, for email notifications)
+SMTP_HOST=
+SMTP_PORT=587
+SMTP_USER=
+SMTP_PASS=
+SMTP_FROM=orders@example.com
+
+# Nostr (shop's private key hex for sending DMs)
+NOSTR_PRIVATE_KEY=
+
+# Server
+PORT=3141