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-member-expression-literals/lib/index.js

@@ -0,0 +1,29 @@
+"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-member-expression-literals",
+    visitor: {
+      MemberExpression: {
+        exit({
+          node
+        }) {
+          const prop = node.property;
+          if (!node.computed && _core.types.isIdentifier(prop) && !_core.types.isValidES3Identifier(prop.name)) {
+            node.property = _core.types.stringLiteral(prop.name);
+            node.computed = true;
+          }
+        }
+      }
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map