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/timer-reset.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: "M10 2h4", key: "n1abiw" }],
+  ["path", { d: "M12 14v-4", key: "1evpnu" }],
+  ["path", { d: "M4 13a8 8 0 0 1 8-7 8 8 0 1 1-5.3 14L4 17.6", key: "1ts96g" }],
+  ["path", { d: "M9 17H4v5", key: "8t5av" }]
+];
+const TimerReset = createLucideIcon("timer-reset", __iconNode);
+
+export { __iconNode, TimerReset as default };
+//# sourceMappingURL=timer-reset.mjs.map