Hide menu pictures only inside the menu frames

The hidden-texture list stayed active in a game; a game texture made at the
address of a freed menu picture was skipped (rendering glitches in-game).
Hiding now applies only while the main menu's frame or the in-game options
draw over the menu background.

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

src/mods/hud.h

@@ -48,8 +48,9 @@ int HandleCanvas(void* event, int (*body)(void* context), void* context);
 int RenderMenuFrame(void* device, bool framed, int (*body)(void* context), void* context);
 int MenuFrameOffsetX();
 
-// Quads drawn with one of these textures (Direct3D surfaces) are left out,
-// on every thread, until the list changes (at most 64).
+// Quads drawn with one of these textures (Direct3D surfaces) are left out
+// inside the frames drawn over the menu background (RenderMenuFrame, the
+// in-game options), until the list changes (at most 64).
 void SetHiddenTextures(void* const* surfaces, int count);
 
 } // namespace mods::hud