feat: add DiscoveredDomain struct and discoverDomains function for metaverse domain discovery

src/DomainDiscovery.hpp

@@ -0,0 +1,15 @@
+#pragma once
+#include <string>
+#include <vector>
+
+// Simple domain record discovered from metaverse API
+struct DiscoveredDomain {
+    std::string name;        // Friendly name if available
+    std::string networkHost; // Hostname or IP
+    int httpPort{40102};     // Control/HTTP port (defaults)
+    int udpPort{40104};      // UDP domain port
+};
+
+// Fetch a list of candidate domains. Non-fatal if empty.
+// Implementation attempts several known metaverse endpoints.
+std::vector<DiscoveredDomain> discoverDomains(int maxDomains = 25);