fix: améliorer Dockerfile avec .dockerignore et logs de débogage

.dockerignore

@@ -0,0 +1,9 @@
+node_modules
+npm-debug.log
+.git
+.gitignore
+README.md
+.env
+.DS_Store
+*.md
+.cleanup-report.md

Dockerfile

@@ -2,13 +2,23 @@ FROM node:18-alpine
 
 WORKDIR /app
 
+# Copy package files
 COPY backend/package*.json ./
 
-RUN npm install --production && npm cache clean --force
+# Install dependencies with verbose output for debugging
+RUN echo "Installing dependencies..." && \
+    npm install --production && \
+    echo "Dependencies installed successfully" && \
+    npm list --production && \
+    npm cache clean --force
 
+# Copy application code
 COPY backend/src ./src
 COPY frontend ./frontend
 
+# Verify express was installed
+RUN ls -la node_modules | grep express || echo "WARNING: express not found in node_modules"
+
 EXPOSE 4001
 
 CMD ["node", "src/server.js"]