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/align-vertical-distribute-center.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 = [
+  ["path", { d: "M22 17h-3", key: "1lwga1" }],
+  ["path", { d: "M22 7h-5", key: "o2endc" }],
+  ["path", { d: "M5 17H2", key: "1gx9xc" }],
+  ["path", { d: "M7 7H2", key: "6bq26l" }],
+  ["rect", { x: "5", y: "14", width: "14", height: "6", rx: "2", key: "1qrzuf" }],
+  ["rect", { x: "7", y: "4", width: "10", height: "6", rx: "2", key: "we8e9z" }]
+];
+const AlignVerticalDistributeCenter = createLucideIcon(
+  "align-vertical-distribute-center",
+  __iconNode
+);
+
+export { __iconNode, AlignVerticalDistributeCenter as default };
+//# sourceMappingURL=align-vertical-distribute-center.mjs.map