BTHLABS-50: Safari Web extension

Co-authored-by: Tomek Wójcik <labs@tomekwojcik.pl>
Co-committed-by: Tomek Wójcik <labs@tomekwojcik.pl>

services/apple/Shared (Extension)/SafariWebExtensionHandler.h

@@ -0,0 +1,12 @@
+//
+//  SafariWebExtensionHandler.h
+//  Shared (Extension)
+//
+//  Created by Tomek Wójcik on 21/08/2025.
+//
+
+#import <Foundation/Foundation.h>
+
+@interface SafariWebExtensionHandler : NSObject <NSExtensionRequestHandling>
+
+@end

services/apple/Shared (Extension)/SafariWebExtensionHandler.m

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+//
+//  SafariWebExtensionHandler.m
+//  Shared (Extension)
+//
+//  Created by Tomek Wójcik on 21/08/2025.
+//
+
+#import "SafariWebExtensionHandler.h"
+
+#import <SafariServices/SafariServices.h>
+
+@implementation SafariWebExtensionHandler
+
+- (void)beginRequestWithExtensionContext:(NSExtensionContext *)context {
+    NSExtensionItem *request = context.inputItems.firstObject;
+
+    NSUUID *profile;
+    if (@available(iOS 17.0, macOS 14.0, *)) {
+        profile = request.userInfo[SFExtensionProfileKey];
+    } else {
+        profile = request.userInfo[@"profile"];
+    }
+
+    id message;
+    if (@available(iOS 15.0, macOS 11.0, *)) {
+        message = request.userInfo[SFExtensionMessageKey];
+    } else {
+        message = request.userInfo[@"message"];
+    }
+
+    NSLog(@"Received message from browser.runtime.sendNativeMessage: %@ (profile: %@)", message, profile.UUIDString ?: @"none");
+
+    NSExtensionItem *response = [[NSExtensionItem alloc] init];
+    if (@available(iOS 15.0, macOS 11.0, *)) {
+        response.userInfo = @{ SFExtensionMessageKey: @{ @"echo": message } };
+    } else {
+        response.userInfo = @{ @"message": @{ @"echo": message } };
+    }
+
+    [context completeRequestReturningItems:@[ response ] completionHandler:nil];
+}
+
+@end