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/shield-off.mjs

@@ -0,0 +1,30 @@
+/**
+ * @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: "m2 2 20 20", key: "1ooewy" }],
+  [
+    "path",
+    {
+      d: "M5 5a1 1 0 0 0-1 1v7c0 5 3.5 7.5 7.67 8.94a1 1 0 0 0 .67.01c2.35-.82 4.48-1.97 5.9-3.71",
+      key: "1jlk70"
+    }
+  ],
+  [
+    "path",
+    {
+      d: "M9.309 3.652A12.252 12.252 0 0 0 11.24 2.28a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1v7a9.784 9.784 0 0 1-.08 1.264",
+      key: "18rp1v"
+    }
+  ]
+];
+const ShieldOff = createLucideIcon("shield-off", __iconNode);
+
+export { __iconNode, ShieldOff as default };
+//# sourceMappingURL=shield-off.mjs.map