Use sync access for the temp JSON file database

Replace all async reads and writes to the JSON database with the sync
reads and writes to prevent a data corruption race condition where two
requests are processed at the same time and write to the same file, or
one reads while the other writes causing read of partially written data.

server/api/users/[id]/details.get.ts

@@ -13,7 +13,7 @@ const detailsSchema = z.object({
 
 export default defineEventHandler(async (event) => {
 	await requireServerSessionWithAdmin(event);
-	const users = await readUsers();
+	const users = readUsers();
 	const { success, error, data: params } = detailsSchema.safeParse(getRouterParams(event));
 	if (!success) {
 		throw createError({

server/api/users/index.get.ts

@@ -6,7 +6,7 @@ import { readUsers } from "~/server/database"
 
 export default defineEventHandler(async (event) => {
 	const session = await requireServerSessionWithUser(event);
-	const users = await readUsers();
+	const users = readUsers();
 
 	if (session.access === "admin") {
 		return users.map(serverUserToApi);