fix(webview/macos): frameless windows must become key + route input to WKWebView (#51)

* fix(webview/macos): borderless windows must become key + route input to WKWebView

A borderless NSWindow returns NO from -canBecomeKeyWindow by default, so
frameless windows never took key focus and their WKWebView never became first
responder, killing all keyboard and mouse input. Use a keyable NSWindow subclass
for the frameless branch and call makeFirstResponder: on the webview after
setContentView and in Show/Focus.

* style(webview/macos): clang-format the LaufeyKeyableWindow comment

The 4-line comment block above LaufeyKeyableWindow exceeded the 80-col
ColumnLimit, failing the CI clang-format check. Reflow it to fit.

Author: littledivy

webview/src/webview_macos.mm

@@ -191,6 +191,23 @@ static void UnregisterNSWindow(NSWindow* win) {
   g_nswindow_to_laufey_id.erase((__bridge void*)win);
 }
 
+// A borderless NSWindow returns NO from
+// -canBecomeKeyWindow/-canBecomeMainWindow by default, so a frameless window
+// never takes key focus and its WKWebView never becomes first responder —
+// killing all keyboard and mouse input. This subclass forces both to YES so
+// frameless windows behave like normal ones.
+@interface LaufeyKeyableWindow : NSWindow
+@end
+
+@implementation LaufeyKeyableWindow
+- (BOOL)canBecomeKeyWindow {
+  return YES;
+}
+- (BOOL)canBecomeMainWindow {
+  return YES;
+}
+@end
+
 @interface LaufeyScriptMessageHandler : NSObject <WKScriptMessageHandler>
 @property(nonatomic, assign) WKWebViewBackend* backend;
 @property(nonatomic, assign) uint32_t windowId;
@@ -886,6 +903,14 @@ int NSButtonToLaufey(NSInteger buttonNumber) {
                                   NSWindowCollectionBehaviorTransient |
                                   NSWindowCollectionBehaviorIgnoresCycle];
         window = panel;
+      } else if (frameless) {
+        // Borderless windows must be told they can become key/main, otherwise
+        // they receive no keyboard or mouse input (see LaufeyKeyableWindow).
+        window = [[LaufeyKeyableWindow alloc]
+            initWithContentRect:frame
+                      styleMask:style
+                        backing:NSBackingStoreBuffered
+                          defer:NO];
       } else {
         window = [[NSWindow alloc] initWithContentRect:frame
                                              styleMask:style
@@ -981,6 +1006,8 @@ int NSButtonToLaufey(NSInteger buttonNumber) {
       }
 
       [window setContentView:webview];
+      // Route input into the web content once the window becomes key.
+      [window makeFirstResponder:webview];
 
       RegisterNSWindow(window, window_id);
 
@@ -1444,16 +1471,20 @@ static CGFloat PrimaryScreenHeight() {
   dispatch_async(dispatch_get_main_queue(), ^{
     @autoreleasepool {
       NSWindow* win = nil;
+      WKWebView* web = nil;
       {
         std::lock_guard<std::mutex> lock(windows_mutex_);
         auto* state = GetWindow(window_id);
         if (state) {
           win = state->window;
+          web = state->webview;
         }
       }
       if (!win)
         return;
       [win makeKeyAndOrderFront:nil];
+      if (web)
+        [win makeFirstResponder:web];
     }
   });
 }
@@ -1480,16 +1511,20 @@ static CGFloat PrimaryScreenHeight() {
   dispatch_async(dispatch_get_main_queue(), ^{
     @autoreleasepool {
       NSWindow* win = nil;
+      WKWebView* web = nil;
       {
         std::lock_guard<std::mutex> lock(windows_mutex_);
         auto* state = GetWindow(window_id);
         if (state) {
           win = state->window;
+          web = state->webview;
         }
       }
       if (win) {
         [NSApp activateIgnoringOtherApps:YES];
         [win makeKeyAndOrderFront:nil];
+        if (web)
+          [win makeFirstResponder:web];
       }
     }
   });