fix(vpinball): skip SDL_SetWindowIcon on the Emscripten target

SDL3's Emscripten video backend emulates SetWindowIcon by pointing the
page's <link rel="icon"> at a blob: URL of the encoded surface - a
reasonable desktop-icon mapping in general, but unwanted for an
embeddable widget where the host page already has its own favicon.
Verified via examples/basic: after this patch, no rel=icon link is
ever created/mutated while a table runs (previously a consumer had to
work around this with a MutationObserver reverting it every time).

patches/vpinball/0009-emscripten-skip-window-icon.patch

@@ -0,0 +1,25 @@
+diff --git a/src/renderer/Window.cpp b/src/renderer/Window.cpp
+index 3dff060..92a96df 100644
+--- a/src/renderer/Window.cpp
++++ b/src/renderer/Window.cpp
+@@ -264,6 +264,12 @@ Window::Window(const string& title, const Settings& settings, VPXWindowId window
+       m_pixelDensity = 1.f;
+    }
+ 
++#ifndef __EMSCRIPTEN__
++   // SDL3's Emscripten video backend emulates SDL_SetWindowIcon by pointing
++   // the page's <link rel="icon"> at a blob: URL of the encoded surface -
++   // a reasonable desktop-icon mapping in general, but unwanted here where
++   // the embedding page already has its own favicon. Skip it on this target
++   // rather than fight it from the host page's JS.
+    if (auto icon = BaseTexture::CreateFromFile(g_app->m_fileLocator.GetAppPath(FileLocator::AppSubFolder::Assets, "vpinball.png")); icon)
+    {
+       SDL_Surface* pSurface = icon->ToSDLSurface();
+@@ -276,6 +282,7 @@ Window::Window(const string& title, const Settings& settings, VPXWindowId window
+    else {
+       PLOGE << "Failed to load window icon: " << SDL_GetError();
+    }
++#endif
+ 
+    // Check if the platform allows positioning windows (as Wayland forbids it...)
+    {