BREAKING CHANGE(Smartjson): Require TC39 Stage 3 decorators for @foldDec (use accessor), switch foldDec to initializer-based implementation, improve buffer encode/decode handling, bump dependencies and update docs/tests.

test/test.both.ts

@@ -3,7 +3,7 @@ import { tap, expect } from '@git.zone/tstest/tapbundle';
 import * as smartjson from '../ts/index.js';
 
 class SomeClass extends smartjson.Smartjson {
-  @smartjson.foldDec() thisis: string = 'test';
+  @smartjson.foldDec() accessor thisis: string = 'test';
   constructor() {
     super();
     console.log(this.saveableProperties);