Fix Dockerfile for Puppeteer/Chromium support

backend/Dockerfile

@@ -1,36 +1,40 @@
 # Build stage
-FROM node:20-alpine AS builder
+FROM node:20-slim AS builder
 
 WORKDIR /app
 
-# Copy package files
 COPY package*.json ./
-
-# Install dependencies
 RUN npm ci
 
-# Copy source code
 COPY . .
-
-# Build TypeScript
 RUN npm run build
 
 # Production stage
-FROM node:20-alpine
+FROM node:20-slim
+
+# Install Chromium dependencies
+RUN apt-get update && apt-get install -y \
+    chromium \
+    fonts-liberation \
+    libnss3 \
+    libxss1 \
+    libasound2 \
+    libatk-bridge2.0-0 \
+    libgtk-3-0 \
+    --no-install-recommends \
+    && rm -rf /var/lib/apt/lists/*
+
+# Tell Puppeteer to use system Chromium
+ENV PUPPETEER_SKIP_CHROMIUM_DOWNLOAD=true
+ENV PUPPETEER_EXECUTABLE_PATH=/usr/bin/chromium
 
 WORKDIR /app
 
-# Copy package files
 COPY package*.json ./
-
-# Install production dependencies only
 RUN npm ci --only=production
 
-# Copy built code from builder
 COPY --from=builder /app/dist ./dist
 
-# Expose port
 EXPOSE 3010
 
-# Start the application
 CMD ["node", "dist/index.js"]