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/table-rows-split.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: "M14 10h2", key: "1lstlu" }],
+  ["path", { d: "M15 22v-8", key: "1fwwgm" }],
+  ["path", { d: "M15 2v4", key: "1044rn" }],
+  ["path", { d: "M2 10h2", key: "1r8dkt" }],
+  ["path", { d: "M20 10h2", key: "1ug425" }],
+  ["path", { d: "M3 19h18", key: "awlh7x" }],
+  ["path", { d: "M3 22v-6a2 2 135 0 1 2-2h14a2 2 45 0 1 2 2v6", key: "ibqhof" }],
+  ["path", { d: "M3 2v2a2 2 45 0 0 2 2h14a2 2 135 0 0 2-2V2", key: "1uenja" }],
+  ["path", { d: "M8 10h2", key: "66od0" }],
+  ["path", { d: "M9 22v-8", key: "fmnu31" }],
+  ["path", { d: "M9 2v4", key: "j1yeou" }]
+];
+const TableRowsSplit = createLucideIcon("table-rows-split", __iconNode);
+
+export { __iconNode, TableRowsSplit as default };
+//# sourceMappingURL=table-rows-split.mjs.map