fix(clipboard): detect macOS 15.4+ via NSProcessInfo, not respondsToSelector

The respondsToSelector: probe for -accessBehavior / -setAccessBehavior: was
returning NO on macOS Tahoe under the unsigned JVM, causing the example's
Privacy card to claim the API was unsupported even though the runtime does
expose it. Switch to [NSProcessInfo isOperatingSystemAtLeastVersion:] for the
support flag — more reliable, independent of ObjC metadata visibility. The
selector probes on get/set remain as a safety net.

Author: kdroidFilter

clipboard-macos/src/main/native/macos/nucleus_clipboard.m

@@ -18,6 +18,11 @@
 
 static JavaVM *g_jvm = NULL;
 
+static BOOL isMacOS_15_4_or_later(void) {
+    NSOperatingSystemVersion v = { .majorVersion = 15, .minorVersion = 4, .patchVersion = 0 };
+    return [[NSProcessInfo processInfo] isOperatingSystemAtLeastVersion:v];
+}
+
 JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *reserved) {
     (void)reserved;
     g_jvm = vm;
@@ -348,9 +353,6 @@ static jobjectArray toJStringArray(JNIEnv *env, NSArray<NSString *> *items) {
     JNIEnv *env, jclass cls) {
     (void)env; (void)cls;
     @autoreleasepool {
-        NSPasteboard *pb = [NSPasteboard generalPasteboard];
-        BOOL hasGetter = [pb respondsToSelector:NSSelectorFromString(@"accessBehavior")];
-        BOOL hasSetter = [pb respondsToSelector:NSSelectorFromString(@"setAccessBehavior:")];
-        return (hasGetter && hasSetter) ? JNI_TRUE : JNI_FALSE;
+        return isMacOS_15_4_or_later() ? JNI_TRUE : JNI_FALSE;
     }
 }