feat: implement OverteAuth class for OAuth2 authentication in Overte metaverse

src/OverteAuth.hpp

@@ -0,0 +1,41 @@
+// OverteAuth.hpp
+#pragma once
+
+#include <string>
+#include <functional>
+
+// Simple OAuth2 authentication for Overte metaverse
+class OverteAuth {
+public:
+    OverteAuth();
+    ~OverteAuth();
+    
+    // Authenticate with username/password
+    bool login(const std::string& username, const std::string& password, 
+               const std::string& metaverseUrl = "https://mv.overte.org");
+    
+    // Check if we have a valid access token
+    bool isAuthenticated() const { return !m_accessToken.empty(); }
+    
+    // Get current access token
+    const std::string& getAccessToken() const { return m_accessToken; }
+    
+    // Get username
+    const std::string& getUsername() const { return m_username; }
+    
+    // Logout
+    void logout();
+    
+private:
+    std::string m_metaverseUrl;
+    std::string m_accessToken;
+    std::string m_refreshToken;
+    std::string m_username;
+    uint64_t m_tokenExpiresAt{0}; // Unix timestamp
+    
+    // libcurl callback for writing response data
+    static size_t writeCallback(void* contents, size_t size, size_t nmemb, void* userp);
+    
+    // Parse JSON response (simple key-value extraction)
+    static std::string extractJsonString(const std::string& json, const std::string& key);
+};