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-bugfix-safari-rest-destructuring-rhs-array/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 _util = require("./util.js");
+var _default = exports.default = (0, _helperPluginUtils.declare)(api => {
+  const {
+    types: t,
+    assertVersion
+  } = api;
+  assertVersion(7);
+  return {
+    name: "plugin-bugfix-safari-rest-destructuring-rhs-array",
+    visitor: {
+      ArrayPattern(path) {
+        const rhs = (0, _util.shouldTransform)(path);
+        if (rhs) {
+          path.replaceWith(t.arrayPattern([path.node]));
+          rhs.replaceWith(t.arrayExpression([rhs.node]));
+        }
+      }
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map