Enhance OpenGLFence with proper synchronization

- Add FenceStatus enum for status query
- Add m_sync (GLsync) for OpenGL fence synchronization
- Add Signal(value) overload with fence value
- Add Wait(timeoutNs) with timeout support
- Add GetStatus() for async status check
- Add GetCompletedValue() and GetCurrentValue()
- Implement using glSync for proper GPU synchronization
- Replace glFinish blocking with glClientWaitSync

engine/include/XCEngine/RHI/OpenGL/OpenGLFence.h

@@ -6,23 +6,34 @@
 namespace XCEngine {
 namespace RHI {
 
+enum class FenceStatus {
+    Signaled,
+    Unsignaled,
+    Error
+};
+
 class OpenGLFence {
 public:
     OpenGLFence();
     ~OpenGLFence();
 
-    bool Initialize();
+    bool Initialize(bool signaled = false);
     void Shutdown();
 
     void Signal();
-    void Wait();
+    void Signal(uint64_t value);
+    void Wait(uint64_t timeoutNs = UINT64_MAX);
     void Reset();
 
     bool IsSignaled() const;
+    FenceStatus GetStatus() const;
+    uint64_t GetCompletedValue() const;
+    uint64_t GetCurrentValue() const { return m_fenceValue; }
 
 private:
-    unsigned int m_fence;
-    int64_t m_fenceValue;
+    void* m_sync;
+    uint64_t m_fenceValue;
+    uint64_t m_completedValue;
     bool m_signaled;
 };