Sections can be nested inside other Sections via Insert Menu (bypassing drag restriction)

Problem:
Sections are not supposed to be nestable within other Sections. This restriction is correctly enforced when using drag-and-drop — users are prevented from dropping a Section inside another Section.

However, this rule can be bypassed when:

1. A user selects an element inside a Section

2. Then clicks to insert a new Section from the Insert Menu

This results in a Section being nested inside another Section, which breaks intended layout logic and potentially causes rendering or structure issues.

Expected Behavior:

• Inserting a Section should be blocked if the current selection is within a Section

• The Insert Menu should respect the same placement rules as drag-and-drop

Steps to Reproduce:

1. Add a Section to the canvas

2. Select a child element inside that Section

3. Open the Insert Menu and click to insert another Section

4. Observe that the new Section is inserted inside the existing one

Priority:
Medium – breaks structural expectations and could result in confusing or invalid nesting

Suggested Fix:
Add a placement guard to the Insert Menu logic that prevents Sections from being inserted into Sections — regardless of selection context.