Insertion of acc. to drawing page option

Current Behavior:

Global setting “Add accessory shapes when parent shape is added” applies to all accessories.

- No per-product or per-accessory override.

- Kits use a shell parent, causing the empty shell to drop into schematics alongside its real accessories.

Requested Enhancements:

- Per-Accessory Override

-- In Parent Product → Accessories tab, add a checkbox on each accessory row:

--- “Include on add” (default reflects global setting)

--- Allows enabling/disabling automatic dropping of that specific accessory when parent is placed.

- Parent-Shell Drop Control

-- In the same tab (e.g. at the top), add a “Include parent shape on add” checkbox:

--- Default = enabled (matches existing behavior)

--- When unchecked, placing the parent product will not drop its shell shape into the drawing.

Use Case (Kits):

- Parent “Kit Shell” product contains RX and TX accessory boxes.

- User unchecks “Include parent shape on add” to suppress the shell.

- User checks “Include on add” only for RX and TX accessories, so only those drop.