Bug: shape changes in a second window are not saved to the project #88

Problem

• A change of the shape on the card of an object in a second window (open_system) of a project is not saved: the object changes, its line in system.jl keeps the old value
• The change is lost when the project is opened again, and the other participants never see it; expected: saved like the same change in the project's window
• Seen on main 5152a1e (Julia 1.13.0, Windows)

# `dir`: a project as in test/TestLiveProjectOwnTypes.jl, K1 = Block(0.025, 0.005) with a width slider on its card
gui = open_project(dir; display = false)
k1 = only(x for (x, (name, _)) in gui.sync.ids if name === :K1)
second = open_system(gui, only(BeamletOpticsGUI._systems(gui)); display = false)
select!(second, k1)
Makie.set_close_to!(card_widget(second, k1, :width), 40.0)
k1.shape.diameter                                 # 0.04
BeamletOpticsGUI._autosave!(gui; force = true)    # :none
# system.jl still has: @component K1 = Block(0.025, 0.005) pos = (0.0, 0.1, 0.0)

Tasks

• A change of the shape in a second window is saved to the project like one in the project's window
• Undo in either window brings the old shape back, also in the files

Notes

• The second window does not know the code of an object that it did not add itself, so the change reaches no code
• The switch "stop beams" of Feature: the card of a detector switches "stop beams" in place #87 writes its change into every linked window and is not affected