fix: Prevent nodemon restarts during policy creation

- Move temp directory outside app folder to /tmp/minio-webui-temp
- Add nodemon.json to ignore temp, logs, and node_modules
- Add TEMP_DIR environment variable configuration
- Add cleanup routine for old temporary policy files (>1 hour)
- Update both dev and production Dockerfiles
- Update docker-compose configurations

This fixes the 500 error during QuickStartWizard policy creation
caused by nodemon restarting when temporary files were created.

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

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

docker/Dockerfile.backend.dev

@@ -24,8 +24,8 @@ RUN NODE_ENV=development npm install && \
     npm rebuild bcrypt --build-from-source
 
 # Create necessary directories
-RUN mkdir -p logs temp && \
-    chmod 755 logs temp
+RUN mkdir -p logs /tmp/minio-webui-temp && \
+    chmod 755 logs /tmp/minio-webui-temp
 
 # Copy application files
 COPY . .