GPU: Don't load the host's window-minimized bit from a savestate

skipDrawReason was saved whole, including the bit that says the host
window is minimized. A state saved while minimized (a rewind snapshot)
kept it set after loading in a normal window, and the other way round.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

GPU/GPUState.cpp

@@ -313,7 +313,12 @@ void GPUStateCache::DoState(PointerWrap &p) {
 		bool framebufChanged = false;  // legacy
 		Do(p, framebufChanged);
 
+		// Minimized is about the host window now, whatever it was when the state was saved.
+		const u32 hostSkipDraw = skipDrawReason & SKIPDRAW_WINDOW_MINIMIZED;
 		Do(p, skipDrawReason);
+		if (p.mode == p.MODE_READ) {
+			skipDrawReason = (skipDrawReason & ~SKIPDRAW_WINDOW_MINIMIZED) | hostSkipDraw;
+		}
 
 		// Legacy, remove in the next bump.
 		UVScale uv{};