add windows theme source and platform icon resolvers

crates/theme/src/system.rs

@@ -14,7 +14,7 @@ pub struct AccessibilityPreferences {
 
 /// Which adapter produced a [`SystemTheme`].
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq)]
-#[cfg_attr(not(target_os = "linux"), allow(dead_code))]
+#[cfg_attr(not(any(target_os = "linux", target_os = "windows")), allow(dead_code))]
 pub enum SourceKind {
     #[default]
     Fallback,
@@ -22,6 +22,7 @@ pub enum SourceKind {
     Omarchy,
     Kde,
     Gnome,
+    Windows,
 }
 
 impl SourceKind {
@@ -32,6 +33,7 @@ impl SourceKind {
             Self::Omarchy => "Omarchy (colors.toml)",
             Self::Kde => "KDE (kdeglobals)",
             Self::Gnome => "GNOME (portal)",
+            Self::Windows => "Windows 11 (UISettings)",
         }
     }
 }