feat: add Dockerfile - multi-stage Alpine build optimized for production

Multi-stage Dockerfile with:
- Alpine Linux base for minimal size (<300MB target)
- Separate stages for builder, production, worker, and development
- Security-focused with non-root user execution
- VIPS library integration for image processing
- pnpm package manager support
- Health checks and proper signal handling with tini
- Optimized layer caching and dependency installation
- Production and development configurations

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

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

Dockerfile

@@ -0,0 +1,126 @@
+# Multi-stage Dockerfile for AI Bulk Image Renamer
+# Target: Alpine Linux for minimal size (<300MB)
+
+# Build stage
+FROM node:18-alpine AS builder
+
+# Install build dependencies
+RUN apk add --no-cache \
+    python3 \
+    make \
+    g++ \
+    libc6-compat \
+    vips-dev
+
+# Enable pnpm
+RUN corepack enable pnpm
+
+# Set working directory
+WORKDIR /app
+
+# Copy package files
+COPY package.json pnpm-lock.yaml* ./
+COPY packages/*/package.json ./packages/*/
+
+# Install dependencies
+RUN pnpm install --frozen-lockfile
+
+# Copy source code
+COPY . .
+
+# Build all packages
+RUN pnpm build
+
+# Prune dev dependencies
+RUN pnpm prune --prod
+
+# Production stage
+FROM node:18-alpine AS production
+
+# Install runtime dependencies
+RUN apk add --no-cache \
+    vips \
+    curl \
+    tini \
+    dumb-init \
+    && addgroup -g 1001 -S nodejs \
+    && adduser -S nodeuser -u 1001
+
+# Enable pnpm
+RUN corepack enable pnpm
+
+# Set working directory
+WORKDIR /app
+
+# Copy package files and node_modules from builder
+COPY --from=builder --chown=nodeuser:nodejs /app/package.json ./
+COPY --from=builder --chown=nodeuser:nodejs /app/node_modules ./node_modules
+COPY --from=builder --chown=nodeuser:nodejs /app/packages ./packages
+
+# Create necessary directories
+RUN mkdir -p /app/logs /app/uploads /app/temp \
+    && chown -R nodeuser:nodejs /app
+
+# Switch to non-root user
+USER nodeuser
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=60s --retries=3 \
+    CMD curl -f http://localhost:3000/health || exit 1
+
+# Expose port
+EXPOSE 3000
+
+# Use tini as PID 1
+ENTRYPOINT ["/sbin/tini", "--"]
+
+# Default command (can be overridden)
+CMD ["pnpm", "start"]
+
+# Worker stage (for background processing)
+FROM production AS worker
+
+# Override default command for worker
+CMD ["pnpm", "start:worker"]
+
+# Development stage
+FROM node:18-alpine AS development
+
+# Install development dependencies
+RUN apk add --no-cache \
+    python3 \
+    make \
+    g++ \
+    libc6-compat \
+    vips-dev \
+    git \
+    curl
+
+# Enable pnpm
+RUN corepack enable pnpm
+
+# Create user
+RUN addgroup -g 1001 -S nodejs \
+    && adduser -S nodeuser -u 1001
+
+WORKDIR /app
+
+# Copy package files
+COPY package.json pnpm-lock.yaml* ./
+COPY packages/*/package.json ./packages/*/
+
+# Install all dependencies (including dev)
+RUN pnpm install --frozen-lockfile
+
+# Create necessary directories
+RUN mkdir -p /app/logs /app/uploads /app/temp \
+    && chown -R nodeuser:nodejs /app
+
+# Switch to non-root user
+USER nodeuser
+
+# Expose port
+EXPOSE 3000
+
+# Start development server
+CMD ["pnpm", "dev"]