fix: add proper Dockerfiles for backend and frontend, simplify docker-compose

backend/Dockerfile

@@ -1,47 +1,15 @@
-# Build stage
-FROM node:20-alpine AS builder
-
-WORKDIR /app
-
-# Copy package files
-COPY package*.json ./
-
-# Install dependencies
-RUN npm ci
-
-# Copy source code
-COPY tsconfig.json ./
-COPY src ./src
-
-# Build TypeScript
-RUN npm run build
-
-# Production stage
 FROM node:20-alpine
 
 WORKDIR /app
 
-# Install dumb-init for proper signal handling
-RUN apk add --no-cache dumb-init
-
-# Copy package files
 COPY package*.json ./
+RUN npm ci
 
-# Install production dependencies only
-RUN npm ci --only=production
+COPY tsconfig.json ./
+COPY src ./src
 
-# Copy built app from builder
-COPY --from=builder /app/dist ./dist
+RUN npm run build
 
-# Expose port
 EXPOSE 5000
 
-# Health check
-HEALTHCHECK --interval=30s --timeout=10s --start-period=40s --retries=3 \
-  CMD node -e "require('http').get('http://localhost:5000/health', (r) => {if (r.statusCode !== 200) throw new Error(r.statusCode)})"
-
-# Use dumb-init to handle signals properly
-ENTRYPOINT ["dumb-init", "--"]
-
-# Start application
 CMD ["node", "dist/index.js"]