Ability to build the entire repo

It does not seem to be possible to build //.... If I select Bazel build package recursively I have to select a package and // is not an option. I have tons of packages so it'd be really nice to be able to just build all of them.

Start by tracing the “Bazel build package recursively” command and its package-selection flow; the issue does not name a file or test. Make the repository-wide // target selectable and verify that choosing it can build all packages without requiring a specific package.

Written by the indexing model from the issue text.