v0.81.0

### [0.81.0] - 2026-09-15
#### ✨ Highlights

`pixi run --script` can now run `conda-script` files directly from HTTP or HTTPS URLs, including GitHub Gists. Pixi downloads the script, reuses its cached environment, and runs it without requiring a local file.

#### Added

- Add remote url support to conda-script by @ruben-arts in [#6981](https://github.com/prefix-dev/pixi/pull/6981)
- Add PrefixPlatformMismatchError for source build prefixes by @hunger in [#6984](https://github.com/prefix-dev/pixi/pull/6984)
- Show the build platform of nested derived environments by @hunger in [#6987](https://github.com/prefix-dev/pixi/pull/6987)


#### Changed

- Track the platform of a derived environment explicitly by @hunger in [#6985](https://github.com/prefix-dev/pixi/pull/6985)
- Keep nested derived environments on the build platform by @hunger in [#6986](https://github.com/prefix-dev/pixi/pull/6986)


#### Documentation

- Explain how source build-dependencies are built when cross-compiling by @hunger in [#6988](https://github.com/prefix-dev/pixi/pull/6988)


#### Fixed

- Use only tombi for TOML formatting by @Hofer-Julian in [#6982](https://github.com/prefix-dev/pixi/pull/6982)


#### Refactor

- Return CLI exit codes from main by @baszalmstra in [#6975](https://github.com/prefix-dev/pixi/pull/6975)


#### New Contributors
* @prefix-dev-pixi-upgrades[bot] made their first contribution in [#6980](https://github.com/prefix-dev/pixi/pull/6980)