uv does not auto-load .env files like pipenv did

Package version (if known): 1.9

## Describe the bug
When pipenv is used as the python package manager, any local `.env` file is automatically loaded by `pipenv run` operations. It's not the case for `uv run` operations. The .env file is not loaded automatically unless `export UV_ENV_FILE=.env`.

This might be a case of [Hyrum's law](https://www.hyrumslaw.com/), so I can probably live with whatever decision. Should be communicated in release notes at least if same behavior not kept.