Add sourcekit_bazel_bsp

[maxwellE]

Adds this new module to the BCR

[bazel-io]

Hello @bazelbuild/bcr-maintainers, modules without existing maintainers (sourcekit_bazel_bsp) have been updated in this PR.
Please review the changes. You can view a diff against the previous version in the "Generate module diff" check.

[kotlaja]

Can you please add github_user_id and github to the maintainer info?

[bazel-io]

Hello @bazelbuild/bcr-maintainers, modules without existing maintainers (sourcekit_bazel_bsp) have been updated in this PR.
Please review the changes. You can view a diff against the previous version in the "Generate module diff" check.

[bkolb]

Is there anything left to do for this PR? It would be great to have that usable for the registry

[maxwellE]

Is there anything left to do for this PR? It would be great to have that usable for the registry

This is blocked until the macOS executors can resolve this issue error: 'sourcekit_bazel_bsp~': package 'sourcekit_bazel_bsp~' is using Swift tools version 6.1.0 but the installed version is 6.0.3

We need a newer version of the Swift Toolchain to use this module.

[maxwellE]

@kotlaja Is there a timeline for supporting the Swift 6.1.0 toolchain on the macos agents?

[meteorcloudy]

@maxwellE Can you try to install it with shell_commands in presubmit.yml file?

[rockbruno]

Opened a new PR with the newest version here, will define a no-op target if it doesn't have Xcode 26 installed similarly to what I've seen has been done to other swift modules in the past.
#6018