Wayland Support

### Expected behaviour
Running WindTerm with Wayland should be possible

### Actual behaviour
WindTerm crashes.

**Commands:**
`export QT_QPA_PLATFORM=wayland`
`./WindTerm`

**Output:**
Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, xcb.

### Steps to reproduce
Force Wayland platform usage with export QT_QPA_PLATFORM=wayland
Run WindTerm
Crash

Start by reproducing the reported launch with QT_QPA_PLATFORM=wayland and ./WindTerm, then inspect how WindTerm packages and discovers Qt platform plugins. Done means the application starts under forced Wayland usage without the missing-plugin crash, while existing platform options continue to work.

Written by the indexing model from the issue text.