fix(desktop): correct maximize bounds, floating restore, and pause sk…

[bruh-raw]

What & why

1. Window Maximize & Floating Bounds: Fixes an issue on Windows where un-maximizing a window into floating mode, moving/resizing it, and re-maximizing causes the window to shift to the right and overflow the monitor. Synchronizes frame.maximizedBounds with monitor work area (bounds minus taskbar insets) and persists floating window coordinates.
2. CPU Usage When Minimized: Pauses the Compose Skia rendering loop while the window is minimized to the taskbar. Gating App() on !windowState.isMinimized stops invisible 60 FPS recompositions and drops CPU usage to 0.0% while background audio playback continues seamlessly.

Linked issue

Closes #2604

Checklist

• This PR addresses an accepted issue (linked above)
• I wrote or personally reviewed every line of this change
• I tested it on Android and/or Desktop (say which, and how)
  Tested on Windows 11 desktop:
• Verified floating window resizing, moving, maximizing, restoring, and closing retains correct bounds with no off-screen shifts or taskbar clipping.
• Verified CPU drops to 0.0% in Task Manager when minimized to taskbar while music continues playing.