fix(docker): simplify deployment by removing nginx and exposing backend on port 80

- Remove nginx service from docker-compose.yml to eliminate configuration issues
- Expose backend directly on port 80 for direct access without reverse proxy
- Update BASE_URL and FRONTEND_URL environment variables to use port 80
- Add data volume mount for daemon storage at /app/data
- Add docker-compose.txt to .gitignore to exclude temporary files
- Add LINUX_DOCKER_FIX.md documentation with setup instructions and troubleshooting
- Simplify deployment configuration for Linux environments where nginx events section was causing startup failures

.gitignore

@@ -37,3 +37,4 @@ frontend/.env.production.local
 frontend/dist/
 backend/build/
 backend/users1.json.backup
+docker-compose.txt