Picture-in-Picture (PiP) and floating window support for CarPlay display

This feature request identifies a significant gap in DiPlay's integration with older Android head unit ecosystems, specifically the lack of `Picture-in-Picture` (PiP) and `floating window features`. Users of older vehicle models rely on `third-party launchers` for `quick vehicle controls`, and the absence of PiP prevents seamless multitasking between CarPlay and native car functions. This limitation forces users to choose between full-screen CarPlay and access to essential vehicle controls, degrading the overall in-car experience. Implementing PiP would enable CarPlay to function as an overlay, allowing simultaneous access to other Android applications or car system interfaces. This feature is crucial for enhancing usability and market competitiveness, particularly for users with less integrated infotainment systems, and represents an opportunity to differentiate by offering a more flexible and integrated user experience.