Add Docker deployment setup with health check endpoint

- Add multi-stage Dockerfile with standalone Next.js output
- Add docker-compose.yml with Caddy reverse proxy
- Add nginx configs for local and SSL setups
- Add Caddyfile for automatic HTTPS
- Add docker-entrypoint.sh for runtime config
- Add .env.example and .dockerignore
- Add comprehensive Docker README
- Add /api/health endpoint for container health checks
- Configure next.config.ts for standalone output

docker/Dockerfile

@@ -0,0 +1,90 @@
+# Synapsis - Multi-stage Production Dockerfile
+# This Dockerfile creates a production-ready image that:
+# - Keeps source files immutable (prevents accidental modifications)
+# - Optimizes build size with multi-stage approach
+# - Runs as non-root user for security
+
+# ============================================
+# Stage 1: Dependencies
+# ============================================
+FROM node:22-alpine AS deps
+RUN apk add --no-cache libc6-compat openssl
+
+WORKDIR /app
+
+# Copy package files for efficient layer caching
+COPY package.json package-lock.json* ./
+
+# Install production dependencies only (using ci for reproducible builds)
+RUN npm ci --only=production --ignore-scripts && npm cache clean --force
+
+# ============================================
+# Stage 2: Builder
+# ============================================
+FROM node:22-alpine AS builder
+RUN apk add --no-cache libc6-compat openssl
+
+WORKDIR /app
+
+# Copy dependencies from deps stage
+COPY --from=deps /app/node_modules ./node_modules
+
+# Copy all source files
+COPY . .
+
+# Set environment variables for build
+ENV NODE_ENV=production
+ENV NEXT_TELEMETRY_DISABLED=1
+
+# Build the Next.js application
+RUN npm run build
+
+# ============================================
+# Stage 3: Production Runner
+# ============================================
+FROM node:22-alpine AS runner
+RUN apk add --no-cache libc6-compat openssl
+
+WORKDIR /app
+
+# Create non-root user for security
+RUN addgroup --system --gid 1001 nodejs && \
+    adduser --system --uid 1001 nextjs
+
+# Set production environment
+ENV NODE_ENV=production
+ENV NEXT_TELEMETRY_DISABLED=1
+ENV PORT=3000
+ENV HOSTNAME="0.0.0.0"
+
+# Copy public assets
+COPY --from=builder /app/public ./public
+
+# Copy Next.js build output
+COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
+COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
+
+# Copy drizzle migrations for runtime database updates
+COPY --from=builder --chown=nextjs:nodejs /app/drizzle ./drizzle
+COPY --from=builder --chown=nextjs:nodejs /app/drizzle.config.ts ./
+COPY --from=builder --chown=nextjs:nodejs /app/package.json ./
+
+# Copy entrypoint script
+COPY --from=builder --chown=nextjs:nodejs /app/docker/docker-entrypoint.sh ./
+RUN chmod +x ./docker-entrypoint.sh
+
+# Switch to non-root user
+USER nextjs
+
+# Expose the application port
+EXPOSE 3000
+
+# Health check to ensure container is running properly
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD node -e "require('http').get('http://localhost:3000/api/health', (r) => r.statusCode === 200 ? process.exit(0) : process.exit(1))"
+
+# Set the entrypoint
+ENTRYPOINT ["./docker-entrypoint.sh"]
+
+# Default command (can be overridden)
+CMD ["node", "server.js"]