feat: add Docker support with single-port deployment

Add complete Docker configuration for containerized deployment:
- Multi-stage Dockerfile using official Bun runtime
- docker-compose.yml for single-port stack orchestration
- Host-mounted database volume with auto-initialization
- Custom database init script using bun:sqlite
- Entrypoint script for seamless database setup
- Environment configuration template
- Comprehensive DOCKER.md documentation

Key features:
- Single exposed port (3001) serving both API and frontend
- Database persists in ./data directory on host
- Auto-creates database from template on first startup
- Health checks for monitoring
- Architecture-agnostic (works on x86 and ARM64)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

.env.docker.example

@@ -0,0 +1,26 @@
+# Docker Environment Configuration
+# Copy this file to .env and update with your values
+
+# ============================================
+# Application Settings
+# ============================================
+NODE_ENV=production
+PORT=3001
+LOG_LEVEL=debug
+
+# ============================================
+# Security (IMPORTANT: Change in production!)
+# ============================================
+# Generate a secure JWT secret with: openssl rand -base64 32
+JWT_SECRET=change-this-in-production-use-openssl-rand-base64-32
+
+# ============================================
+# CORS Configuration
+# ============================================
+# Your application's public URL (e.g., https://awards.example.com)
+VITE_APP_URL=
+
+# Comma-separated list of allowed origins for CORS
+# Only needed if not using same domain deployment
+# Example: https://awards.example.com,https://www.awards.example.com
+ALLOWED_ORIGINS=