refactor(layouts): extract independent komorebi-layouts crate

This commit moves layout-related code into a new workspace crate
komorebi-layouts, with the intention of re-using it all in komorebi for
Mac instead of maintaining two separate implementations.

komorebi-layouts/src/cycle_direction.rs

@@ -0,0 +1,36 @@
+use std::num::NonZeroUsize;
+
+use clap::ValueEnum;
+use serde::Deserialize;
+use serde::Serialize;
+use strum::Display;
+use strum::EnumString;
+
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, Display, EnumString, ValueEnum)]
+#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
+pub enum CycleDirection {
+    Previous,
+    Next,
+}
+
+impl CycleDirection {
+    #[must_use]
+    pub const fn next_idx(&self, idx: usize, len: NonZeroUsize) -> usize {
+        match self {
+            Self::Previous => {
+                if idx == 0 {
+                    len.get() - 1
+                } else {
+                    idx - 1
+                }
+            }
+            Self::Next => {
+                if idx == len.get() - 1 {
+                    0
+                } else {
+                    idx + 1
+                }
+            }
+        }
+    }
+}