feat(window_manager): add get_virtual_desktop_bounds() for multi-monitor support

catser/window_manager.py

@@ -244,6 +244,8 @@ class WindowManager:
     def get_work_area() -> Tuple[int, int, int, int]:
         """
         Returns desktop work area (left, top, right, bottom) excluding the taskbar.
+        NOTE: This only covers the *primary* monitor's work area.
+        Use get_virtual_desktop_bounds() for full multi-monitor extent.
         """
         SPI_GETWORKAREA = 0x0030
         rect = wintypes.RECT()
@@ -252,3 +254,32 @@ class WindowManager:
         # Fallback to full screen
         w, h = WindowManager.get_screen_dimensions()
         return (0, 0, w, h)
+
+    @staticmethod
+    def get_virtual_desktop_bounds() -> Tuple[int, int, int, int]:
+        """
+        Returns the bounding rectangle of the full virtual desktop spanning ALL monitors.
+
+        On a single-monitor system this equals get_screen_dimensions().
+        On multi-monitor systems it covers every display, including those with
+        negative coordinates (monitors left of / above the primary).
+
+        Returns:
+            (left, top, right, bottom) in virtual-desktop pixel coordinates.
+        """
+        SM_XVIRTUALSCREEN  = 76   # Left edge of virtual desktop
+        SM_YVIRTUALSCREEN  = 77   # Top edge of virtual desktop
+        SM_CXVIRTUALSCREEN = 78   # Total width of virtual desktop
+        SM_CYVIRTUALSCREEN = 79   # Total height of virtual desktop
+
+        vx = user32.GetSystemMetrics(SM_XVIRTUALSCREEN)
+        vy = user32.GetSystemMetrics(SM_YVIRTUALSCREEN)
+        vw = user32.GetSystemMetrics(SM_CXVIRTUALSCREEN)
+        vh = user32.GetSystemMetrics(SM_CYVIRTUALSCREEN)
+
+        if vw == 0 or vh == 0:
+            # GetSystemMetrics failed – fall back to primary screen
+            w, h = WindowManager.get_screen_dimensions()
+            return (0, 0, w, h)
+
+        return (vx, vy, vx + vw, vy + vh)