Custom blur region for panel background

[luisbocanegra]

So I have been inspecting how the panel background blur works:

• The blur region (panelMask) is read from the panel background svg file qml side
• The background region is then read from c++ side
• And applied some lines below using KWindowEffects::enableBlurBehind

So I thought what if I replace the panelMask with my own? And I did!

• I created a function that receives the panel background QRect, the radius and a offset thing also coming from the default panel
• With that then creates a rounded QPainterPath which is then returned to qml with the propper format

It works and is beautiful!

2024-06-02_12-28-32.mp4

Todo:

• Making sure the blur is updated correctly when the panel transforms/moves
• #52