refactor(layouts): add darwin feature gate and expand win32 feature gate

This commit builds on the newly introduced komorebi-layouts crate to
make it suitable for wholesale adoption in komorebi for Mac.

komorebi-layouts/src/layout.rs

@@ -2,6 +2,7 @@ use serde::Deserialize;
 use serde::Serialize;
 
 use super::Arrangement;
+#[cfg(feature = "win32")]
 use super::CustomLayout;
 use super::DefaultLayout;
 use super::Direction;
@@ -10,6 +11,7 @@ use super::Direction;
 #[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
 pub enum Layout {
     Default(DefaultLayout),
+    #[cfg(feature = "win32")]
     Custom(CustomLayout),
 }
 
@@ -18,6 +20,7 @@ impl Layout {
     pub fn as_boxed_direction(&self) -> Box<dyn Direction> {
         match self {
             Layout::Default(layout) => Box::new(*layout),
+            #[cfg(feature = "win32")]
             Layout::Custom(layout) => Box::new(layout.clone()),
         }
     }
@@ -26,6 +29,7 @@ impl Layout {
     pub fn as_boxed_arrangement(&self) -> Box<dyn Arrangement> {
         match self {
             Layout::Default(layout) => Box::new(*layout),
+            #[cfg(feature = "win32")]
             Layout::Custom(layout) => Box::new(layout.clone()),
         }
     }