fix: keep Junbae clear of the editor minimap

[changchanghwang]

#21

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Description of change

• Fix Junbae following the end of the rendered text after recent VS Code updates.
• Position Junbae and the timer relative to the visible code area.
• Keep a 5vw gap from the right edge without overlapping the minimap.
• Preserve the existing top and bottom placement modes.

Pull-Request Checklist

• [ x ] Code is up-to-date with the main branch
• [ x ] There are new or updated unit tests validating the change
• [ x ] Documentation has been updated to reflect this change
• [ x ] The new commits follow conventions explained in CONTRIBUTING.md