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/alarm-smoke.mjs

@@ -0,0 +1,23 @@
+/**
+ * @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: "M11 21c0-2.5 2-2.5 2-5", key: "1sicvv" }],
+  ["path", { d: "M16 21c0-2.5 2-2.5 2-5", key: "1o3eny" }],
+  ["path", { d: "m19 8-.8 3a1.25 1.25 0 0 1-1.2 1H7a1.25 1.25 0 0 1-1.2-1L5 8", key: "1bvca4" }],
+  [
+    "path",
+    { d: "M21 3a1 1 0 0 1 1 1v2a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V4a1 1 0 0 1 1-1z", key: "x3qr1j" }
+  ],
+  ["path", { d: "M6 21c0-2.5 2-2.5 2-5", key: "i3w1gp" }]
+];
+const AlarmSmoke = createLucideIcon("alarm-smoke", __iconNode);
+
+export { __iconNode, AlarmSmoke as default };
+//# sourceMappingURL=alarm-smoke.mjs.map