refactor(core): use fractional indexing for sorting (#5809)

use https://github.com/rocicorp/fractional-indexing to enable better sorting logic for crdt app

yarn.lock

@@ -354,6 +354,7 @@ __metadata:
     express: "npm:^4.18.2"
     fake-indexeddb: "npm:^5.0.0"
     foxact: "npm:^0.2.20"
+    fractional-indexing: "npm:^3.2.0"
     graphql: "npm:^16.8.1"
     html-webpack-plugin: "npm:^5.5.3"
     idb: "npm:^8.0.0"