v2.0

What's new

• NVIDIA support: uses Vulkan renderer instead of OpenGL (nvdec hardware decoding)
• Lock screen: wallpaper pauses instantly on lock, resumes on unlock (D-Bus signal, zero polling cost)
• Fix: minimized/hidden windows no longer keep wallpaper paused
• Fix: mpv window ID set before init (no more black frame timing issues)
• Fix: duration/position signals corrected to double precision
• Fix: GPU detection cached, runs once instead of once per screen
• Fix: play() now uses retry logic same as refreshSource()