Support allowsBackForwardNavigationGestures (#4453)

* ## Summary

I have successfully implemented support for `allowsBackForwardNavigationGestures` in Wails v3. Here's what I accomplished:

### Investigation Results
- **Issue Status**: The feature was **NOT** previously implemented in Wails v3
- **go-webview2**: This library is Windows-only and doesn't provide macOS WKWebView features
- **Need**: A native implementation was required specifically for macOS WKWebView

### Implementation Details
1. **Added new option**: `AllowsBackForwardNavigationGestures u.Bool` to `MacWebviewPreferences`
2. **Extended C bridge**: Updated the C struct to pass the preference to Objective-C code
3. **Implemented WKWebView setting**: Added code to set `webView.allowsBackForwardNavigationGestures` during initialization
4. **Updated preference processing**: Extended the Go code to handle the new preference

### Key Files Modified
- `v3/pkg/application/webview_window_options.go`: Added the preference option
- `v3/pkg/application/webview_window_darwin.go`: Implemented the C bridge and WKWebView configuration

### Usage Example
```go
window.SetOptions(application.WebviewWindowOptions{
    Mac: application.MacWindow{
        WebviewPreferences: application.MacWebviewPreferences{
            AllowsBackForwardNavigationGestures: u.True(),
        },
    },
})
```

### Testing
- ✅ Code compiles successfully
- ✅ Created working example demonstrating the feature
- ✅ Follows existing Wails v3 patterns and conventions

### Benefits
- Provides native macOS two-finger swipe navigation
- Better performance than JavaScript alternatives
- Maintains accessibility features
- Seamless integration with existing Wails v3 API

The implementation is ready for testing and could be submitted as a PR to the Wails repository. The feature addresses the exact requirements from GitHub issue #1857 and provides both specific and API-consistent access to WKWebView's navigation gesture functionality.

* Perfect! I have:

1. ✅ Removed the `NAVIGATION_GESTURES_FEATURE.md` file
2. ✅ Removed the `example_navigation_gestures.go` file 
3. ✅ Updated the `UNRELEASED_CHANGELOG.md` with a FIX entry

The changelog entry properly documents that this fix adds support for `allowsBackForwardNavigationGestures` in macOS WKWebView to enable two-finger swipe navigation gestures, referencing issue #1857.

The implementation is now clean and ready, with only the essential code changes remaining and the changelog properly updated to reflect the fix.

v3/UNRELEASED_CHANGELOG.md

@@ -24,6 +24,7 @@ After processing, the content will be moved to the main changelog and this file
 
 ## Fixed
 <!-- Bug fixes -->
+- Add support for `allowsBackForwardNavigationGestures` in macOS WKWebView to enable two-finger swipe navigation gestures (#1857)
 - Fixes issue where onClick didn't work for menu items initially set as disabled by @leaanthony in [PR #4469](https://github.com/wailsapp/wails/pull/4469). Thanks to @IanVS for the initial investigation.
 - Fix Vite server not being cleaned up when build fails (#4403)
 

v3/pkg/application/webview_window_darwin.go

@@ -18,6 +18,7 @@ struct WebviewPreferences {
     bool *TabFocusesLinks;
     bool *TextInteractionEnabled;
     bool *FullscreenEnabled;
+    bool *AllowsBackForwardNavigationGestures;
 };
 
 extern void registerListener(unsigned int event);
@@ -101,6 +102,11 @@ void* windowNew(unsigned int id, int width, int height, bool fraudulentWebsiteWa
 	WKWebView* webView = [[WKWebView alloc] initWithFrame:frame configuration:config];
 	[webView autorelease];
 
+    // Set allowsBackForwardNavigationGestures if specified
+    if (preferences.AllowsBackForwardNavigationGestures != NULL) {
+        webView.allowsBackForwardNavigationGestures = *preferences.AllowsBackForwardNavigationGestures;
+    }
+
 	[view addSubview:webView];
 
     // support webview events
@@ -1182,6 +1188,9 @@ func (w *macosWebviewWindow) getWebviewPreferences() C.struct_WebviewPreferences
 	if wvprefs.FullscreenEnabled.IsSet() {
 		result.FullscreenEnabled = bool2CboolPtr(wvprefs.FullscreenEnabled.Get())
 	}
+	if wvprefs.AllowsBackForwardNavigationGestures.IsSet() {
+		result.AllowsBackForwardNavigationGestures = bool2CboolPtr(wvprefs.AllowsBackForwardNavigationGestures.Get())
+	}
 
 	return result
 }

v3/pkg/application/webview_window_options.go

@@ -441,6 +441,8 @@ type MacWebviewPreferences struct {
 	TextInteractionEnabled u.Bool
 	// FullscreenEnabled will enable fullscreen
 	FullscreenEnabled u.Bool
+	// AllowsBackForwardNavigationGestures enables horizontal swipe gestures for back/forward navigation
+	AllowsBackForwardNavigationGestures u.Bool
 }
 
 // MacTitleBar contains options for the Mac titlebar