Implement GX Thread for Asynchronous Rendering

- Introduced a new GX thread to handle the rendering pipeline, allowing the game thread to post commands without blocking.
- Added `gx_thread.h` and `gx_thread.cpp` to manage the command ring buffer and thread synchronization.
- Updated `vi.cpp` to utilize the GX thread for rendering tasks, improving frame pacing and responsiveness.
- Modified `main.cpp` to configure and start the GX thread, ensuring it integrates with the existing rendering workflow.
- Enhanced `openxr_integration.cpp` to register the GX thread with OpenXR for better performance in VR scenarios.
- Refactored `settings_overlay.cpp` to remove unnecessary waits for the frame worker, as the overlay now draws directly into the game thread's ImGui frame.
- Improved error handling and logging in the GX thread to capture exceptions during command execution.

runtime/src/settings_overlay.cpp

@@ -2143,9 +2143,9 @@ void ReleaseControllers() noexcept {
 }
 
 void Draw() noexcept {
-    // Wait for the frame worker's DONE phase: it has replayed the previous frame's ImGui draw lists
-    // and started the next ImGui frame, so all overlay callers can now safely issue ImGui commands.
-    aurora_wait_for_frame_worker();
+    // The overlay draws into the game thread's own ImGui frame
+    // (aurora_imgui_host_frame_begin); the worker replays a copy of the draw
+    // data, so there is nothing to wait for here.
     // Explain fallback without interrupting gameplay or capturing input.
     static std::string shownXrError;
     static double xrNoticeUntil = 0.0;