Fix: npm install issue in Dockerfile - use npm install directly without deprecated flags

Dockerfile

@@ -5,11 +5,9 @@ WORKDIR /app
 # Copy package files
 COPY backend/package*.json ./
 
-# Install dependencies with npm ci for reproducibility
-RUN npm ci --only=production || npm install --production
-
-# Verify critical dependencies are installed
-RUN test -d node_modules/express || (echo "ERROR: express not installed" && exit 1)
+# Install dependencies
+RUN npm install --production --no-audit --no-fund && \
+    if [ ! -d node_modules/express ]; then echo "ERROR: express not installed" && exit 1; fi
 
 # Copy application code
 COPY backend/src ./src