fix: fix XWayland cursor truncation on fractional-scaled multi-monitor

[glyvut]

Scale XWayland-only xdg_output position and size by maxDPR so that the
root window bounding box matches the physical-pixel coordinate space
that XWayland clients actually receive.

将 XWayland 专用的 xdg_output 的 position 和 size 均按 maxDPR 缩放，
使 root window bounding box 与 XWayland 客户端实际收到的物理像素
坐标空间一致，修复分数缩放多显示器下光标坐标被截断的问题。

Log: 修复分数缩放多屏XWayland光标截断
PMS: BUG-370341
Influence: XWayland xdg_output按maxDPR缩放对齐物理坐标空间

Summary by Sourcery

Align XWayland xdg_output geometry with the physical-pixel coordinate space used by XWayland clients to prevent cursor truncation on fractional-scaled multi-monitor setups.

Bug Fixes:

• Correct XWayland xdg_output position and size calculations by applying an appropriate scale factor so the root window bounding box matches XWayland’s physical-pixel space.

Enhancements:

• Track and update a dedicated XWayland WXdgOutputManager with the current maximum device pixel ratio to keep XWayland output geometry in sync with display scaling changes.