feat: add settings normalization and status storage

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

test/storage.test.js

@@ -0,0 +1,35 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { DEFAULT_SETTINGS, normalizeSettings } from '../src/lib/storage.js';
+
+test('normalizeSettings falls back to defaults for missing input', () => {
+  assert.deepEqual(normalizeSettings(), DEFAULT_SETTINGS);
+  assert.deepEqual(normalizeSettings({}), DEFAULT_SETTINGS);
+  assert.deepEqual(DEFAULT_SETTINGS, { apiKey: '', threshold: 5, minViews: 10000 });
+});
+
+test('normalizeSettings trims the key and coerces numeric strings', () => {
+  assert.deepEqual(normalizeSettings({ apiKey: '  abc123  ', threshold: '7.5', minViews: '20000' }), {
+    apiKey: 'abc123',
+    threshold: 7.5,
+    minViews: 20000,
+  });
+});
+
+test('normalizeSettings replaces invalid thresholds with the default', () => {
+  for (const threshold of [-1, 0, 'abc', '', null, NaN, Infinity]) {
+    assert.equal(normalizeSettings({ threshold }).threshold, 5, String(threshold));
+  }
+});
+
+test('normalizeSettings replaces invalid minViews with the default and floors decimals', () => {
+  for (const minViews of [-5, 'abc', '', null, NaN]) {
+    assert.equal(normalizeSettings({ minViews }).minViews, 10000, String(minViews));
+  }
+  assert.equal(normalizeSettings({ minViews: 1500.7 }).minViews, 1500);
+  assert.equal(normalizeSettings({ minViews: 0 }).minViews, 0);
+});
+
+test('normalizeSettings ignores a non-string key', () => {
+  assert.equal(normalizeSettings({ apiKey: 12345 }).apiKey, '');
+});