Include "Target Branch Workflow" settings in project templates/project exports
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### Proposal
#### Summary
Target Branch Workflow settings should be included when creating a new project from a template or when exporting/importing a project.
#### Problem
Currently, when creating a new project from a template or exporting/importing a project, the Target Branch Workflow settings (from a project's "Settings" -> "Merge Requests" -> "Merge request branch workflow") are not copied over. This requires manual reconfiguration of these settings for each new project, which is time-consuming and error-prone for teams that standardize on specific workflow configurations.
#### Proposed Solution
Include Target Branch Workflow settings in the following operations:
* **Project templates**: When creating a new project from a template, copy the template's Target Branch Workflow configuration
* **Project export/import**: Include Target Branch Workflow settings in the exported project data and restore them during import
_Based on the [documentation](https://docs.gitlab.com/user/group/custom_project_templates/#what-is-copied-from-the-templates), both creating a new project and exporting a project would seem to use the same codebase._
#### Benefits
* Reduces manual configuration overhead for new projects
* Ensures consistency across projects using the same template
* Improves team productivity and reduces setup errors
* Maintains workflow standardization across project migrations
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