Add sync error logging, extend error flash, fix unload saves

- Log workforce sync errors to backend stdout so they appear in docker logs
- Extend error flash from 5s to 15s so errors are readable
- Replace sendBeacon (POST-only) with keepalive fetch (PUT) on unload —
  sendBeacon was hitting 404s on all three unload saves

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/node_modules/es-object-atoms/test/index.js

@@ -0,0 +1,38 @@
+'use strict';
+
+var test = require('tape');
+
+var $Object = require('../');
+var isObject = require('../isObject');
+var ToObject = require('../ToObject');
+var RequireObjectCoercible = require('..//RequireObjectCoercible');
+
+test('errors', function (t) {
+	t.equal($Object, Object);
+	// @ts-expect-error
+	t['throws'](function () { ToObject(null); }, TypeError);
+	// @ts-expect-error
+	t['throws'](function () { ToObject(undefined); }, TypeError);
+	// @ts-expect-error
+	t['throws'](function () { RequireObjectCoercible(null); }, TypeError);
+	// @ts-expect-error
+	t['throws'](function () { RequireObjectCoercible(undefined); }, TypeError);
+
+	t.deepEqual(RequireObjectCoercible(true), true);
+	t.deepEqual(ToObject(true), Object(true));
+	t.deepEqual(ToObject(42), Object(42));
+	var f = function () {};
+	t.equal(ToObject(f), f);
+
+	t.equal(isObject(undefined), false);
+	t.equal(isObject(null), false);
+	t.equal(isObject({}), true);
+	t.equal(isObject([]), true);
+	t.equal(isObject(function () {}), true);
+
+	var obj = {};
+	t.equal(RequireObjectCoercible(obj), obj);
+	t.equal(ToObject(obj), obj);
+
+	t.end();
+});