implemented frontend including separate message system; started to implement backend

yjs-poll/node_modules/lib0/hash/sha256.node.js

@@ -0,0 +1,10 @@
+import { createHash } from 'node:crypto'
+
+/**
+ * @param {Uint8Array} data
+ */
+export const digest = data => {
+  const hasher = createHash('sha256')
+  hasher.update(data)
+  return hasher.digest()
+}