Add Docker support with comprehensive deployment options

- Add multi-stage Dockerfile with optimized builds for Go backend and Node.js frontend
- Create docker-entrypoint.sh script for managing both services with PM2
- Add .dockerignore for optimal build context
- Update README.md with Docker deployment documentation including:
  - Docker build and run instructions
  - Persistent data configuration with volume mounts
  - Complete environment variable reference table
  - Docker Compose example configuration

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Dockerfile

@@ -0,0 +1,85 @@
+# Multi-stage Dockerfile for Claude Code Proxy
+# Builds both Go proxy server and Remix frontend in a single container
+
+# Stage 1: Build Go Backend
+FROM golang:1.21-alpine AS go-builder
+
+WORKDIR /app
+
+# Install build dependencies
+RUN apk add --no-cache git
+
+# Copy Go modules
+COPY proxy/go.mod proxy/go.sum ./proxy/
+WORKDIR /app/proxy
+RUN go mod download
+
+# Copy Go source code
+COPY proxy/ ./
+RUN go build -o /app/bin/proxy cmd/proxy/main.go
+
+# Stage 2: Build Node.js Frontend
+FROM node:20-alpine AS node-builder
+
+WORKDIR /app
+
+# Copy package files
+COPY web/package*.json ./web/
+WORKDIR /app/web
+RUN npm ci --only=production
+
+# Copy web source code and build
+COPY web/ ./
+RUN npm run build
+
+# Stage 3: Production Runtime
+FROM node:20-alpine
+
+WORKDIR /app
+
+# Install process manager for running multiple services
+RUN npm install -g pm2
+
+# Create app user for security
+RUN addgroup -g 1001 -S appgroup && \
+    adduser -S appuser -u 1001 -G appgroup
+
+# Copy built Go binary
+COPY --from=go-builder /app/bin/proxy ./bin/proxy
+RUN chmod +x ./bin/proxy
+
+# Copy built Remix application
+COPY --from=node-builder /app/web/build ./web/build
+COPY --from=node-builder /app/web/package*.json ./web/
+COPY --from=node-builder /app/web/node_modules ./web/node_modules
+
+# Create data directory for SQLite database
+RUN mkdir -p /app/data && chown -R appuser:appgroup /app
+
+# Copy startup script
+COPY docker-entrypoint.sh ./
+RUN chmod +x docker-entrypoint.sh
+
+# Environment variables with defaults
+ENV PORT=3001
+ENV WEB_PORT=5173
+ENV READ_TIMEOUT=600
+ENV WRITE_TIMEOUT=600
+ENV IDLE_TIMEOUT=600
+ENV ANTHROPIC_FORWARD_URL=https://api.anthropic.com
+ENV ANTHROPIC_VERSION=2023-06-01
+ENV ANTHROPIC_MAX_RETRIES=3
+ENV DB_PATH=/app/data/requests.db
+
+# Expose ports
+EXPOSE 3001 5173
+
+# Switch to app user
+USER appuser
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
+    CMD wget --no-verbose --tries=1 --spider http://localhost:${PORT}/health || exit 1
+
+# Start both services
+CMD ["./docker-entrypoint.sh"]