Replace Dockerized PostgreSQL with managed/remote PostgreSQL due to timezone configuration issues #1
Description
Currently, the backend uses a Dockerized PostgreSQL instance for local development. We are encountering repeated startup failures caused by PostgreSQL timezone configuration (Asia/Calcutta, which is invalid in newer PostgreSQL versions).
To simplify setup and avoid environment-specific database issues, we should remove the Docker-based PostgreSQL dependency and switch to a managed or remote PostgreSQL instance.