Do not apply synthetic momentum for mouse wheel based scrolling by default

Many mice wheels have their own physical momentum

src/calibre/gui2/momentum_scroll.py

@@ -54,6 +54,8 @@ class MomentumSettings(NamedTuple):
     # How much to scale scroll amounts by
     x_multiplier: float = 1
     y_multiplier: float = 1
+    # Synthesize momentum for mouse wheels or trackpads that send NoScrollPhase events
+    synthesize_without_gestures: bool = False
 
 
 class MomentumScroller:
@@ -63,7 +65,7 @@ class MomentumScroller:
     Behavior by platform/device:
     - macOS trackpad: Uses system-provided momentum (ScrollMomentum phase)
     - Linux trackpad: Has phases but sometimes no momentum, so we synthesize it when needed
-    - Mouse wheel (all platforms): No phases, we synthesize momentum
+    - Mouse wheel (all platforms): No phases, we synthesize momentum if enabled in settings
     '''
 
     def __init__(self, scroll_area: QAbstractScrollArea, settings: MomentumSettings = MomentumSettings()):
@@ -113,14 +115,14 @@ class MomentumScroller:
 
         match event.phase():
             case Qt.ScrollPhase.NoScrollPhase:
-                # Record sample
+                # typically generated by mouse wheel and on windows
+                if not self.settings.synthesize_without_gestures:
+                    return False
                 self.samples.append(ScrollSample(dx, dy, current_time))
-                # Apply immediate scroll
-                self._do_scroll(dx, dy)
-                # Reset momentum timer - will start coasting after input stops
                 self.momentum_timer.stop()
-                self.momentum_timer.start(self.settings.timer_interval_ms)
                 self._last_scroll_end_time = current_time
+                self._do_scroll(dx, dy)
+                self.momentum_timer.start(self.settings.timer_interval_ms)
 
             case Qt.ScrollPhase.ScrollBegin:
                 # User started a new scroll gesture
@@ -335,7 +337,8 @@ class MomentumScrollMixin:
         if (not self._momentum_scroller.settings.enable_x and event.angleDelta().x() != 0) or (
                 not self._momentum_scroller.settings.enable_y and event.angleDelta().y() != 0):
             return super().wheelEvent(event)
-        self._momentum_scroller.handle_wheel_event(event)
+        if not self._momentum_scroller.handle_wheel_event(event):
+            return super().wheelEvent(event)
         event.accept()
 
     def stopMomentumScroll(self):