Initial commit: Lightning Lottery - Bitcoin Lightning Network powered lottery

Features:
- Lightning Network payments via LNbits integration
- Provably fair draws using CSPRNG
- Random ticket number generation
- Automatic payouts with retry/redraw logic
- Nostr authentication (NIP-07)
- Multiple draw cycles (hourly, daily, weekly, monthly)
- PostgreSQL and SQLite database support
- Real-time countdown and payment animations
- Swagger API documentation
- Docker support

Stack:
- Backend: Node.js, TypeScript, Express
- Frontend: Next.js, React, TailwindCSS, Redux
- Payments: LNbits

back_end/env.example

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+# Lightning Lottery Backend - Environment Configuration
+# Copy this file to .env and fill in your values
+
+# ======================
+# Server Configuration
+# ======================
+PORT=3000
+APP_BASE_URL=http://localhost:3000
+FRONTEND_BASE_URL=http://localhost:3001
+# Optional: comma-separated list to override allowed origins
+# CORS_ALLOWED_ORIGINS=http://localhost:3001,https://app.yourdomain.com
+NODE_ENV=development
+
+# ======================
+# Database Configuration
+# ======================
+# Database type: "postgres" or "sqlite"
+DATABASE_TYPE=sqlite
+
+# Database connection
+# For PostgreSQL: postgresql://username:password@host:port/database
+# For SQLite: ./data/lightning_lotto.db (relative path)
+DATABASE_URL=./data/lightning_lotto.db
+
+# PostgreSQL example:
+# DATABASE_TYPE=postgres
+# DATABASE_URL=postgresql://user:password@localhost:5432/lightning_lotto
+
+# ======================
+# LNbits Configuration
+# ======================
+# Your LNbits instance URL
+LNBITS_API_BASE_URL=https://legend.lnbits.com
+
+# LNbits admin/invoice key (required for creating invoices and payouts)
+# Get this from your LNbits wallet settings
+LNBITS_ADMIN_KEY=your_lnbits_admin_key_here
+
+# Webhook secret for validating LNbits payment notifications
+# Choose a random secret string
+LNBITS_WEBHOOK_SECRET=your_webhook_secret_here
+
+# ======================
+# Security Configuration
+# ======================
+# Secret for signing JWT tokens (use a strong random string)
+# Generate with: openssl rand -hex 32
+JWT_SECRET=your_jwt_secret_here_change_in_production
+
+# Admin API key for admin endpoints
+# Generate with: openssl rand -hex 32
+ADMIN_API_KEY=your_admin_api_key_here_change_in_production
+
+# ======================
+# Scheduler Configuration
+# ======================
+# How often to check for draws that need to be executed (in seconds)
+DRAW_SCHEDULER_INTERVAL_SECONDS=60
+
+# How often to generate future cycles (in seconds)
+CYCLE_GENERATOR_INTERVAL_SECONDS=300
+
+# ======================
+# Lottery Configuration
+# ======================
+# Default ticket price in satoshis
+DEFAULT_TICKET_PRICE_SATS=1000
+
+# House fee percentage (0-100)
+# Example: 5 means 5% fee, winner gets 95% of pot
+DEFAULT_HOUSE_FEE_PERCENT=5
+
+# Maximum Lightning payout attempts before drawing a new winner
+PAYOUT_MAX_ATTEMPTS=2
+
+# ======================
+# Notes
+# ======================
+# - SQLite is perfect for development and testing (no setup required!)
+# - Use PostgreSQL for production deployments
+# - Never commit the actual .env file to version control
+# - Use strong, unique secrets in production
+# - Keep your LNbits keys secure
+# - Test with small amounts first