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-reserved-words/lib/index.js

@@ -0,0 +1,23 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var _helperPluginUtils = require("@babel/helper-plugin-utils");
+var _core = require("@babel/core");
+var _default = exports.default = (0, _helperPluginUtils.declare)(api => {
+  api.assertVersion(7);
+  return {
+    name: "transform-reserved-words",
+    visitor: {
+      "BindingIdentifier|ReferencedIdentifier"(path) {
+        if (!_core.types.isValidES3Identifier(path.node.name)) {
+          path.scope.rename(path.node.name);
+        }
+      }
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map