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/parking-meter.mjs

@@ -0,0 +1,26 @@
+/**
+ * @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 15h2", key: "199qp6" }],
+  ["path", { d: "M12 12v3", key: "158kv8" }],
+  ["path", { d: "M12 19v3", key: "npa21l" }],
+  [
+    "path",
+    {
+      d: "M15.282 19a1 1 0 0 0 .948-.68l2.37-6.988a7 7 0 1 0-13.2 0l2.37 6.988a1 1 0 0 0 .948.68z",
+      key: "1jofit"
+    }
+  ],
+  ["path", { d: "M9 9a3 3 0 1 1 6 0", key: "jdoeu8" }]
+];
+const ParkingMeter = createLucideIcon("parking-meter", __iconNode);
+
+export { __iconNode, ParkingMeter as default };
+//# sourceMappingURL=parking-meter.mjs.map