feat(store): load/save and target accessors with validation

tests/localstorage-shim.js

@@ -0,0 +1,9 @@
+export function createLocalStorage() {
+  const data = new Map();
+  return {
+    getItem(k) { return data.has(k) ? data.get(k) : null; },
+    setItem(k, v) { data.set(k, String(v)); },
+    removeItem(k) { data.delete(k); },
+    clear() { data.clear(); },
+  };
+}

tests/store.test.js

@@ -0,0 +1,51 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { Store } from '../src/store.js';
+import { createLocalStorage } from './localstorage-shim.js';
+
+function freshStore() {
+  return new Store({ storage: createLocalStorage() });
+}
+
+test('Store: starts empty', () => {
+  const s = freshStore();
+  assert.equal(s.getTarget('strength'), null);
+});
+
+test('Store: setTarget validates via parseTarget', () => {
+  const s = freshStore();
+  assert.equal(s.setTarget('strength', '25M'), true);
+  assert.equal(s.getTarget('strength'), 25_000_000);
+});
+
+test('Store: setTarget rejects invalid and keeps previous', () => {
+  const s = freshStore();
+  s.setTarget('strength', 25_000_000);
+  assert.equal(s.setTarget('strength', 'abc'), false);
+  assert.equal(s.getTarget('strength'), 25_000_000);
+});
+
+test('Store: targets are per-attribute', () => {
+  const s = freshStore();
+  s.setTarget('strength', 25_000_000);
+  s.setTarget('speed', 50_000_000);
+  assert.equal(s.getTarget('strength'), 25_000_000);
+  assert.equal(s.getTarget('speed'), 50_000_000);
+});
+
+test('Store: persists across instances via storage', () => {
+  const storage = createLocalStorage();
+  const a = new Store({ storage });
+  a.setTarget('strength', 25_000_000);
+  const b = new Store({ storage });
+  assert.equal(b.getTarget('strength'), 25_000_000);
+});
+
+test('Store: corrupted JSON is wiped with a warning', () => {
+  const storage = createLocalStorage();
+  storage.setItem('tat.targets', '{not json');
+  const warnings = [];
+  const s = new Store({ storage, onWarn: (m) => warnings.push(m) });
+  assert.equal(s.getTarget('strength'), null);
+  assert.equal(warnings.length, 1);
+});