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/@babel/plugin-transform-class-properties/lib/index.js

@@ -0,0 +1,22 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var _helperPluginUtils = require("@babel/helper-plugin-utils");
+var _helperCreateClassFeaturesPlugin = require("@babel/helper-create-class-features-plugin");
+var _default = exports.default = (0, _helperPluginUtils.declare)((api, options) => {
+  api.assertVersion("^7.0.0-0 || ^8.0.0-0");
+  return (0, _helperCreateClassFeaturesPlugin.createClassFeaturePlugin)({
+    name: "transform-class-properties",
+    api,
+    feature: _helperCreateClassFeaturesPlugin.FEATURES.fields,
+    loose: options.loose,
+    manipulateOptions(opts, parserOpts) {
+      parserOpts.plugins.push("classProperties", "classPrivateProperties");
+    }
+  });
+});
+
+//# sourceMappingURL=index.js.map