Links (#615)

* add URL support to Label element and XML parsing

* refactor Label URL handling to use getter method in setURL

* implement URL opening confirmation dialog and platform-specific URL handling

* fix: fixed build errors

* remove: delete test link label from worlds.xml

* refactor: remove URL handling from Label class and XML parsing

* refactor: clean up Label class by removing unnecessary whitespace and improving code readability

* refactor: remove unused URL member from Label class

* refactor: remove unused URL attribute from XML UI documentation and related code

* refactor: improve code readability by adding whitespace and formatting adjustments in Label class

* refactor: improve whitespace consistency in Label class and add URL opening functionality in libcore

src/util/platform.cpp

@@ -65,14 +65,31 @@ int platform::get_process_id() {
     return GetCurrentProcessId(); 
 }
 
+bool platform::openURL(const std::string& url) {
+    if (url.empty()) return false;
+    // UTF-8 → UTF-16
+    int wlen = MultiByteToWideChar(CP_UTF8, 0, url.c_str(), -1, nullptr, 0);
+    if (wlen <= 0) return false;
+
+    std::wstring wurl(wlen, L'\0');
+    MultiByteToWideChar(CP_UTF8, 0, url.c_str(), -1, &wurl[0], wlen);
+
+    HINSTANCE result = ShellExecuteW(
+        nullptr, L"open", wurl.c_str(), nullptr, nullptr, SW_SHOWNORMAL
+    );
+
+    return reinterpret_cast<intptr_t>(result) > 32;
+}
+
 #else // _WIN32
 
 #include <unistd.h>
+#include <sys/wait.h>
 #include "frontend/locale.hpp"
 
 void platform::configure_encoding() {
 }
-
+ 
 std::string platform::detect_locale() {
     const char* const programLocaleName = setlocale(LC_ALL, nullptr);
     const char* const preferredLocaleName =
@@ -92,6 +109,24 @@ void platform::sleep(size_t millis) {
 int platform::get_process_id() {
     return getpid();
 }
+
+bool platform::openURL(const std::string& url) {
+    if (url.empty()) return false;
+    pid_t pid = fork();
+    if (pid == 0) {
+#ifdef __APPLE__
+        execlp("open", "open", url.c_str(), (char*)nullptr);
+#else
+        execlp("xdg-open", "xdg-open", url.c_str(), (char*)nullptr);
+#endif
+        _exit(127);
+    } else if (pid > 0) {
+        int status = 0;
+        waitpid(pid, &status, 0);
+        return WIFEXITED(status) && WEXITSTATUS(status) == 0;
+    }
+    return false;
+}
 #endif // _WIN32
 
 void platform::open_folder(const std::filesystem::path& folder) {