💄(frontend) Use StyledLink for sub doc tree

[pvrnn]

Purpose

• Closes [Bug] Ctrl-click (or middle click) child document does not open in new tab #1951
• Replace ButtonBox by StyledLink in DocSubPageItem so ctrl+click on the sub document title open a new browser tab

Before

734a-8294-43f9-8c66-ef692e3a55b1.mp4

After

Recording.2026-03-22.201225.1.mp4

External contributions

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