Minimizing or closing hides the window instead of leaving a taskbar
entry; only "Beenden" in the tray right-click menu really exits. Tray
callbacks route through a queue instead of touching Tk directly from
pystray's thread (same pattern as the earlier serial-thread fix).
Also fixes the build script: PyInstaller failed on the network share
while copying Tcl/Tk tzdata (path-length issue), so building now
happens in a local temp copy instead of directly on Z:.
Adds an info button that explains the MCP server's available tools.
Avoids the cmd.exe flash from double-clicking run_desktop.bat and
gives a proper double-click .exe like VersaGUI.exe. Must be deployed
locally (%LOCALAPPDATA%) -- Windows silently refuses to load the
_internal DLLs when the .exe sits on the Z: network share, no error
shown. build_and_deploy.ps1 handles build + local copy in one step.
