Add scroll wheel zoom support and dynamic scrollbar management

When zoom mode is enabled, scrollbars now appear and support mouse
wheel zooming with Cmd+scroll or Opt+scroll. When zoom is disabled,
scrollbars are hidden and the view fits the window. This makes zoom
functional on devices without trackpads.

Author: stuffbucket

virtualization_view.m

@@ -416,6 +416,13 @@ - (void)setupGraphicWindow
                                                                    return event;
                                                                }];
 
+    // Add scroll wheel event monitor for zoom functionality
+    [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskScrollWheel
+                                          handler:^NSEvent *(NSEvent *event) {
+                                              [self handleScrollWheel:event];
+                                              return event;
+                                          }];
+
     // Create scroll view for the virtual machine view
     NSScrollView *scrollView = [self createScrollViewForVirtualMachineView:_virtualMachineView];
     [_window setContentView:scrollView];
@@ -638,6 +645,7 @@ - (void)showErrorAlertWithMessage:(NSString *)message error:(NSError *)error
 - (void)toggleZoomMode:(id)sender
 {
     _isZoomEnabled = !_isZoomEnabled;
+    NSScrollView *scrollView = (NSScrollView *)_window.contentView;
 
     // Reset zoom when zoom mode is disabled.
     if (!_isZoomEnabled) {
@@ -646,7 +654,20 @@ - (void)toggleZoomMode:(id)sender
                 [context setDuration:0.3];
                 [[_window.contentView animator] setMagnification:1.0];
             }
-            completionHandler:nil];
+            completionHandler:^{
+                // Hide scrollers when zoom is disabled
+                if ([scrollView isKindOfClass:[NSScrollView class]]) {
+                    scrollView.hasVerticalScroller = NO;
+                    scrollView.hasHorizontalScroller = NO;
+                }
+            }];
+    } else {
+        // Show scrollers when zoom is enabled (they'll auto-hide when not needed)
+        if ([scrollView isKindOfClass:[NSScrollView class]]) {
+            scrollView.hasVerticalScroller = YES;
+            scrollView.hasHorizontalScroller = YES;
+            scrollView.autohidesScrollers = YES;
+        }
     }
 }
 
@@ -698,6 +719,40 @@ - (void)handleMagnification:(NSMagnificationGestureRecognizer *)recognizer
     [scrollView setMagnification:newMagnification centeredAtPoint:centeredPoint];
 }
 
+// Handles scroll wheel events for zooming when Command or Option key is held.
+// This provides zoom functionality for mice and non-trackpad devices.
+- (void)handleScrollWheel:(NSEvent *)event
+{
+    if (!_isZoomEnabled) {
+        return;
+    }
+
+    // Only zoom if Command or Option key is held
+    if (!(event.modifierFlags & NSEventModifierFlagCommand) &&
+        !(event.modifierFlags & NSEventModifierFlagOption)) {
+        return;
+    }
+
+    NSScrollView *scrollView = (NSScrollView *)_window.contentView;
+    if (![scrollView isKindOfClass:[NSScrollView class]]) {
+        return;
+    }
+
+    // Calculate zoom delta (scrolling up = zoom in, down = zoom out)
+    CGFloat zoomDelta = event.scrollingDeltaY * 0.01; // Scale factor for smooth zooming
+    CGFloat currentMagnification = scrollView.magnification;
+    CGFloat newMagnification = currentMagnification + zoomDelta;
+
+    // Clamp to min/max magnification
+    newMagnification = MIN(scrollView.maxMagnification, MAX(scrollView.minMagnification, newMagnification));
+
+    // Get mouse location for centered zooming
+    NSPoint mouseLocation = [_window.contentView convertPoint:event.locationInWindow fromView:nil];
+    NSPoint centeredPoint = [scrollView.contentView convertPoint:mouseLocation fromView:_window.contentView];
+
+    [scrollView setMagnification:newMagnification centeredAtPoint:centeredPoint];
+}
+
 // When the mouse approaches the window's edges, this handler adjusts the scroll position
 // to provide a smooth panning experience without requiring manual scroll input.
 - (void)handleMouseMovement:(NSEvent *)event