- Discovered devices now populate via a new `discoveredDevices` filter; the
Repeater was referencing a property that did not exist.
- Pairing chains into trust + connect at root scope, so freshly-paired
devices (especially audio headphones) persist in BlueZ and actually
finish connecting instead of flashing "Connected" and disappearing.
- Wrap the device list in a Flickable capped at 400px with a scroll bar
so crowded RF environments do not grow the popup off-screen.
- Reorder MouseAreas so the per-row X button receives clicks instead of
the full-row click handler swallowing them.