style: narrow the manual-resize press state for the pyright gate

The diff-vs-main basedpyright gate flags QRect(self._press_geom) because
only _press_global was narrowed; both are set together in
mousePressEvent, so the extra check is a no-op at runtime.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/aare/gui/widgets/popout_window.py

@@ -196,7 +196,9 @@ class PopoutWindow(QWidget):
         super().mousePressEvent(event)
 
     def mouseMoveEvent(self, event):
-        if self._manual_edges and self._press_global is not None:
+        # Both press fields are set together in mousePressEvent; the second
+        # check exists for the pyright gate, which can't see that pairing.
+        if self._manual_edges and self._press_global is not None and self._press_geom is not None:
             delta = event.globalPosition().toPoint() - self._press_global
             geom = QRect(self._press_geom)
             if self._manual_edges & Qt.Edge.LeftEdge: