Integrate @mieweb/kerebron as a submodule in the UI repository

[garrity-miepub]

Background
We need to add the @mieweb/kerebron repository as a submodule within the mieweb/ui repository. It is critical that this integration uses a submodule (not just a code copy or subtree). See how datavis NITRO was previously set up as a submodule for reference.

Requirements:

• Add @mieweb/kerebron as a submodule to this repository.
• Follow the same pattern as the datavis NITRO submodule integration (structure, directory location, setup scripts, and any config updates).
• Validate the submodule is properly initialized in development and deployment workflows.
• Update any relevant documentation as needed.
• Ensure .gitmodules and related settings reflect the inclusion correctly.

Action Requested:
@ggodlewski – @horner would like you to create a PR to implement this work.

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Reference:

• mieweb/kerebron repo
• Prior submodule: datavis NITRO.

[ggodlewski]

@garrity-miepub @horner @wreiske I don't have access to push branches.