Refactoring of the macOS 26 Title Bar Right-Click Fix Solution

This change has a moderate impact on WebView2Mac. Firstly, the positive impacts include: the remote_cocoa component inherited by WebView2Mac will gain a more reliable mouse event handling mechanism, especially in fullscreen mode on macOS 26, where the right-click context menu functionality will become more stable. The new NSNextStepFrame override mechanism is more robust compared to the previous NSToolbarView swizzling approach, as NSNextStepFrame is the starting point for mouse event hit-testing and cannot be bypassed. Secondly, potential risks include: the new solution is more intrusive, as it overrides internal AppKit methods, which may face compatibility issues in future macOS versions. Components such as hosting_ns_window_bridge in WebView2Mac that rely on specific mouse event handling flows may need to be validated for compatibility with the new mechanism. Since the change involves underlying event handling mechanisms, it is recommended to conduct comprehensive testing of WebView2Mac’s context menu, drag-and-drop operations, and other interactive features.