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/radio.mjs

@@ -0,0 +1,20 @@
+/**
+ * @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: "M16.247 7.761a6 6 0 0 1 0 8.478", key: "1fwjs5" }],
+  ["path", { d: "M19.075 4.933a10 10 0 0 1 0 14.134", key: "ehdyv1" }],
+  ["path", { d: "M4.925 19.067a10 10 0 0 1 0-14.134", key: "1q22gi" }],
+  ["path", { d: "M7.753 16.239a6 6 0 0 1 0-8.478", key: "r2q7qm" }],
+  ["circle", { cx: "12", cy: "12", r: "2", key: "1c9p78" }]
+];
+const Radio = createLucideIcon("radio", __iconNode);
+
+export { __iconNode, Radio as default };
+//# sourceMappingURL=radio.mjs.map