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/minimize-2.mjs

@@ -0,0 +1,19 @@
+/**
+ * @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 = [
+  ["path", { d: "m14 10 7-7", key: "oa77jy" }],
+  ["path", { d: "M20 10h-6V4", key: "mjg0md" }],
+  ["path", { d: "m3 21 7-7", key: "tjx5ai" }],
+  ["path", { d: "M4 14h6v6", key: "rmj7iw" }]
+];
+const Minimize2 = createLucideIcon("minimize-2", __iconNode);
+
+export { __iconNode, Minimize2 as default };
+//# sourceMappingURL=minimize-2.mjs.map