Fix runaway resizing during mixed-DPI window drags

[LunaticGhoulPiano]

Fixes #4600.

Problem

On Windows 11 24H2 with mixed-DPI monitors, dragging a maximized window from a 125% scaled monitor to a 100% scaled monitor can repeatedly enlarge the restored window and keep it attached to the original monitor.

The conservative rectangle adjustment performed during WM_DPICHANGED can move the window back to the previous monitor, causing another DPI transition and creating a resize feedback loop.

Fix

While the window is inside a live move/resize operation, apply the rectangle suggested by WM_DPICHANGED directly.

Outside a live move/resize operation, retain the existing conservative DPI adjustment and monitor-nudge behavior.

Testing

• cargo +nightly fmt --all -- --check

• cargo check --lib

• Tested by repeatedly dragging a winit application between monitors with different DPI scale factors

• Verified with TS Analyzer through eframe

• Confirmed that the window moves to the target monitor without uncontrolled growth

• Tested on all platforms changed

• Added an entry to the changelog module

• Documentation changes are not applicable

• No example changes are required

• No feature-matrix changes are required

[LunaticGhoulPiano]

The CI failures appear unrelated to this PR.

All affected jobs fail during the shared Generate lockfile step before building or testing this change:

error: specification `syn` is ambiguous
help: re-run this command with one of the following specifications
  syn@2.0.119
  syn@3.0.5

The workflow currently runs:

cargo update -p syn --precise 2.0.114

I reproduced the failure locally. Qualifying the package by major version works:

cargo update -p syn@2 --precise 2.0.114