Augment Bazel query syntax to support external modules

### Motivation

Bazel query syntax can capture all packages recursively via `//...` but this only supports the `_main` module.
If you would like to capture EVERYTHING including third-party repositories, there is no such syntax.

This can be useful for things like package_groups where you might want to select everything but toggle away certain groups.

Right now there is no solution this problem except for numerating all your third-party modules manually in the package_group

[Slack thread](https://bazelbuild.slack.com/archives/CA31HN1T3/p1753629794374009) with additional information.

No files, tests, or entry points are named in the issue. Start by reviewing the Bazel query syntax behavior described here and the linked Slack thread; done means a query syntax can capture all packages, including third-party repositories, without manually enumerating external modules.

Written by the indexing model from the issue text.