update visitId hash and expiration logic

src/lib/crypto.ts

@@ -1,4 +1,4 @@
-import { startOfMonth } from 'date-fns';
+import { startOfHour, startOfMonth } from 'date-fns';
 import { hash } from 'next-basics';
 import { v4, v5, validate } from 'uuid';
 
@@ -12,6 +12,12 @@ export function salt() {
   return hash(secret(), ROTATING_SALT);
 }
 
+export function sessionSalt() {
+  const ROTATING_SALT = hash(startOfHour(new Date()).toUTCString());
+
+  return hash(secret(), ROTATING_SALT);
+}
+
 export function uuid(...args: any) {
   if (!args.length) return v4();