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/config.py

@@ -38,7 +38,7 @@ class DisplayManagerConfig:
     apps: dict[str, AppExeConfig] = field(default_factory=dict)
     button_position: str = "top-right"   # top-right | top-left | bottom-right | bottom-left
     button_margin: int = 12              # px from screen edge
-    autolaunch: bool = True              # launch apps on startup if exe exists
+    autolaunch: bool = False             # launch all apps on startup (False = on-demand only)
 
     # ------------------------------------------------------------------ I/O
     @classmethod

display_manager/display_manager.py

@@ -106,6 +106,18 @@ class DisplayManager(QObject):
             self._bring_app(app_id, screen_geo)
 
         self._layout.set(screen_serial, app_id)
+        # Minimize apps not assigned to any screen (free GPU)
+        self._minimize_unassigned()
+
+    def _minimize_unassigned(self) -> None:
+        """Minimize every running app that is not currently assigned to any screen."""
+        assigned = set(
+            self._layout.get(self._screen_serial(s))
+            for s in self._app.screens()
+        ) - {None}
+        for app_id in self._proc_mgr.running_ids():
+            if app_id not in assigned:
+                self._proc_mgr.minimize(app_id)
 
     def _bring_app(self, app_id: str, geo: QRect) -> None:
         self._proc_mgr.bring_to_screen(app_id, geo.x(), geo.y(), geo.width(), geo.height())

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()

display_manager/win32_utils.py

@@ -80,5 +80,10 @@ else:
         _user32.ShowWindow(hwnd, _SW_MAXIMIZE)
         _user32.SetForegroundWindow(hwnd)
 
+    def minimize_window(hwnd: int) -> None:
+        """Minimize a window to taskbar to free GPU resources."""
+        _SW_MINIMIZE = 6
+        _user32.ShowWindow(hwnd, _SW_MINIMIZE)
+
     def is_window_alive(hwnd: int) -> bool:
         return bool(_user32.IsWindow(hwnd))