Function cycle_pkgbuild_view_section 

pub fn cycle_pkgbuild_view_section(app: &mut AppState)

What: Advance the PKGBUILD viewer to the next section (body, ShellCheck, Namcap) and align scroll.

Inputs:

• app: Mutable application state (pkgb_visible should be true when the user triggers this).

Output:

• Updates pkgb_section_cycle and pkgb_scroll in app.

Details:

• Forwards into the details-pane PKGBUILD renderer so event handlers do not reach into private details submodules directly.