feat(subscriptions): add cmd to gen json schema

This commit introduces the 'notification-schema' command to generate a
JSON schema of the Notification struct which gets sent when notifying
subscribers of updates.

komorebi-core/src/arrangement.rs

@@ -1,6 +1,7 @@
 use std::num::NonZeroUsize;
 
 use clap::ArgEnum;
+use schemars::JsonSchema;
 use serde::Deserialize;
 use serde::Serialize;
 use strum::Display;
@@ -341,7 +342,7 @@ impl Arrangement for CustomLayout {
     }
 }
 
-#[derive(Clone, Copy, Debug, Serialize, Deserialize, Display, EnumString, ArgEnum)]
+#[derive(Clone, Copy, Debug, Serialize, Deserialize, Display, EnumString, ArgEnum, JsonSchema)]
 #[strum(serialize_all = "snake_case")]
 pub enum Axis {
     Horizontal,