v3.0.0

Fixed

• The app pinned a full CPU core (~12% of an 8-core machine) for the entire time
  it sat hidden in the system tray. Idle usage is now 0%.

Cause

• Hiding to the tray used ShowWindow(SW_HIDE), which clears WS_VISIBLE.
  Windows does not deliver WM_PAINT to an invisible window, so winit's
  request_redraw produced nothing and eframe was left holding its event loop
  in ControlFlow::Poll, waiting for a RedrawRequested that could never
  arrive. Upstream issue: emilk/egui#3982.
• The window is now minimised with the WS_EX_TOOLWINDOW style instead. It
  stays out of the taskbar and Alt+Tab, but keeps WS_VISIBLE, so repaints are
  still serviced and the event loop parks in ControlFlow::Wait between them.

Changed

• Removed the internal workaround that had to poke a hidden window from another
  thread before it could act on the tray icon, the global hotkey or a second
  launch. A window that can still paint handles those directly.
• The window handle is taken from eframe rather than found
  window title.
• The start-at-login path (--background) re-applies the
  frames, because winit rewrites the extended window style while eframe applies
  the state the window was built with.

Measured

State	2.9.1	3.0.0
Hidden in tray, idle	100% of a core	0%
Window shown, idle	0%	0-2%
Start-at-login, idle	1%	0%

Platforms

• Windows only. Linux and macOS were never affected: X11 a
  redraw requests inside winit instead of going through the display server, and
  both already minimised rather than hiding.

Upgrading

• Drop-in replacement. No data, settings or shortcut chang