Fixes: 1) Update CODEOWNERS to replace ambiguous "@default-owner" with "@@owner"; 2) Correct assignments for docker-compose.yml, .gitignore, .dockerignore, and nginx to "@@maintainer".
Extra: Standardized ownership definitions for improved clarity and maintainability.
Fixes: 1) Update `docker-compose.yml` to use `Dockerfile.app` instead of default build context;
Extra: 1) Add commented-out `storefront` service in `docker-compose.yml` for potential future use; 2) Minor cleanup and structuring of Docker setup;
