fix(display-manager): lazy launch by default + minimize unassigned apps

- autolaunch default: True → False (on-demand only, saves GPU on startup)
- add ProcessManager.minimize() to minimize a window to taskbar
- add win32_utils.minimize_window() (SW_MINIMIZE via user32)
- DisplayManager._minimize_unassigned(): after each app switch, minimize
  every running app not currently assigned to any screen, freeing iGPU
  resources (critical on J6412 UHD 600 with limited EUs)

Background: J6412 Intel UHD 600 has only 16 EUs @ 800 MHz. Running
AR-ECDIS (MapLibre GL) and GPS (OpenLayers) simultaneously consumes ~60%
iGPU. By minimizing inactive apps Windows suspends their GPU presentation
chain, dropping idle GPU load near zero.

AR_electronics — AR-Autopilot Project

display_manager/process_manager.py

@@ -90,6 +90,16 @@ class ProcessManager(QObject):
         win32_utils.move_and_maximize(hwnd, x, y, w, h)
         return True
 
+    def minimize(self, app_id: str) -> None:
+        """Minimize *app_id*'s window to free GPU resources."""
+        handle = self._handles.get(app_id)
+        if handle is None or not handle.is_running():
+            return
+        title_hint = self._config.apps.get(app_id, AppExeConfig()).title_hint
+        hwnd = handle.find_hwnd(title_hint)
+        if hwnd is not None:
+            win32_utils.minimize_window(hwnd)
+
     def is_running(self, app_id: str) -> bool:
         h = self._handles.get(app_id)
         return h is not None and h.is_running()