[WIP] Fix re-staging of files after task execution with ${staged:separator}

[Copilot]

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This section details on the original issue you should resolve

<issue_title>${staged:separator} pattern does not re-stage files after task execution</issue_title>
<issue_description>### Version

latest

Details

When using the ${staged:separator} variable pattern (e.g., --include=${staged:;}) in a task definition, Husky.Net doesn't re-stage files after the task modifies them. This means formatting changes made by tools like jb cleanupcode are left as unstaged modifications in the working tree, while the commit is finalized with the original unformatted content.

The ${staged} pattern (without a separator) works correctly.

Steps to reproduce

1. Configure a pre-commit task using ${staged:;}:

{
   "tasks": [
      {
         "name": "resharper-cleanup",
         "group": "pre-commit",
         "command": "dotnet",
         "pathMode": "relative",
         "include": ["**/*.cs"],
         "args": [
            "jb",
            "cleanupcode",
            "--profile=Built-in: Reformat Code",
            "--include=${staged:;}",
            "MyProject.slnx"
         ]
      }
   ]
}

2. Stage a .cs file that has formatting issues.
3. Run git commit.
4. Observe that the commit contains unformatted code and the formatted changes are left in the working tree unstaged.</issue_description>

Comments on the Issue (you are @copilot in this section)

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