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-literals/lib/index.js

@@ -0,0 +1,31 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var _helperPluginUtils = require("@babel/helper-plugin-utils");
+var _default = exports.default = (0, _helperPluginUtils.declare)(api => {
+  api.assertVersion(7);
+  return {
+    name: "transform-literals",
+    visitor: {
+      NumericLiteral({
+        node
+      }) {
+        if (node.extra && /^0[ob]/i.test(node.extra.raw)) {
+          node.extra = undefined;
+        }
+      },
+      StringLiteral({
+        node
+      }) {
+        if (node.extra && /\\u/i.test(node.extra.raw)) {
+          node.extra = undefined;
+        }
+      }
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map