graphics: stall waitUntilSafeForRendering in its command processor instead of the GPU thread

src/graphics/guest_gpu/graphicsRun.h

@@ -31,6 +31,8 @@ public:
 	[[nodiscard]] bool IsStopping();
 	void               SendCommand(Common::UniqueFunction<void>&& command);
 	void               SendCommandSync(Common::UniqueFunction<void>&& command);
+	// Retries blocked submissions now instead of after the 100 ms stall timeout.
+	void               Wake();
 
 	// Submitted command memory is borrowed and must remain valid until GPU execution completes.
 	void Submit(std::span<const uint32_t> draw_commands,
@@ -87,6 +89,7 @@ private:
 	bool                                           m_processing        = false;
 	bool                                           m_accepting         = true;
 	bool                                           m_stopping          = false;
+	bool                                           m_wake_pending      = false;
 	bool                                           m_shutdown_complete = false;
 	// Completion callbacks can outlive GuestGpu during renderer shutdown.
 	std::shared_ptr<std::binary_semaphore> m_suspend_point_ready =