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/mouse-off.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: "M12 6v.343", key: "1gyhex" }],
+  ["path", { d: "M18.218 18.218A7 7 0 0 1 5 15V9a7 7 0 0 1 .782-3.218", key: "ukzz01" }],
+  ["path", { d: "M19 13.343V9A7 7 0 0 0 8.56 2.902", key: "104jy9" }],
+  ["path", { d: "M22 22 2 2", key: "1r8tn9" }]
+];
+const MouseOff = createLucideIcon("mouse-off", __iconNode);
+
+export { __iconNode, MouseOff as default };
+//# sourceMappingURL=mouse-off.mjs.map