Implement mutable mapping for client entities

Create a simple Map like class for storing and keeping track of client
entities that are synced from the server and have local editable state.
This will form the basis for storing entities on the client and should
replace the immutable concept used be the ClientSchedule class.

plugins/payload-client-map.ts

@@ -0,0 +1,25 @@
+import { Info } from "~/shared/utils/luxon";
+
+export default definePayloadPlugin(() => {
+	definePayloadReducer(
+		"ClientMap",
+		data => {
+			if (!(data instanceof ClientMap)) {
+				return;
+			}
+			const accountStore = useAccountStore();
+			return {
+				timezone: accountStore.activeTimezone,
+				locale: accountStore.activeLocale,
+				api: data.toApi(false),
+			};
+		},
+	);
+	definePayloadReviver(
+		"ClientMap",
+		({ timezone, locale, api }) => {
+			const zone = Info.normalizeZone(timezone);
+			return ClientMap.fromApi(api, { zone, locale })
+		},
+	);
+});