Update BushelCloud and CelestraCloud to reference shared setup-mistkit action from MistKit

[leogdion]

Summary

The setup-mistkit composite GitHub Action (which replaces local MistKit path dependencies with remote branch references) is currently duplicated in both example repos:

• Examples/BushelCloud/.github/actions/setup-mistkit/action.yml
• Examples/CelestraCloud/.github/actions/setup-mistkit/action.yml

A shared version has been added to the MistKit repo root in PR #205:
.github/actions/setup-mistkit/action.yml

Work Required

Once PR #205 is merged, update each subrepo to replace its local copy with a reference to the MistKit-hosted version:

- uses: brightdigit/MistKit/.github/actions/setup-mistkit@main
  with:
    branch: ${{ env.MISTKIT_BRANCH }}

Then delete the local setup-mistkit action from each subrepo.

Affected Repos

• BushelCloud
• CelestraCloud