Implement access controlled edit schedule endpoint

Add PATCH /api/schedule endpoint for editing the schedule in a manner
that's access controlled.

shared/utils/changes.ts

@@ -0,0 +1,21 @@
+import type { ChangeRecord } from "~/shared/types/schedule";
+
+export function applyChange<T extends { id: string }>(change: ChangeRecord<T>, data: T[]) {
+	const index = data.findIndex(item => item.id === change.data.id);
+	if (change.op === "del") {
+		if (index !== -1)
+			data.splice(index, 1);
+	} else if (change.op === "set") {
+		if (index !== -1)
+			data.splice(index, 1, change.data);
+		else
+			data.push(change.data)
+	}
+}
+
+export function applyChangeArray<T extends { id: string }>(changes: ChangeRecord<T>[], data: T[]) {
+	// Note: quadratic complexity due to findIndex in applyChange
+	for (const change of changes) {
+		applyChange(change, data);
+	}
+}