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/lucide-react/dist/esm/icons/ferris-wheel.mjs

@@ -0,0 +1,24 @@
+/**
+ * @license lucide-react v1.24.0 - ISC
+ *
+ * This source code is licensed under the ISC license.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
+import createLucideIcon from '../createLucideIcon.mjs';
+
+const __iconNode = [
+  ["circle", { cx: "12", cy: "12", r: "2", key: "1c9p78" }],
+  ["path", { d: "M12 2v4", key: "3427ic" }],
+  ["path", { d: "m6.8 15-3.5 2", key: "hjy98k" }],
+  ["path", { d: "m20.7 7-3.5 2", key: "f08gto" }],
+  ["path", { d: "M6.8 9 3.3 7", key: "1aevh4" }],
+  ["path", { d: "m20.7 17-3.5-2", key: "1liqo3" }],
+  ["path", { d: "m9 22 3-8 3 8", key: "wees03" }],
+  ["path", { d: "M8 22h8", key: "rmew8v" }],
+  ["path", { d: "M18 18.7a9 9 0 1 0-12 0", key: "dhzg4g" }]
+];
+const FerrisWheel = createLucideIcon("ferris-wheel", __iconNode);
+
+export { __iconNode, FerrisWheel as default };
+//# sourceMappingURL=ferris-wheel.mjs.map