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/defaultAttributes.mjs

@@ -0,0 +1,21 @@
+/**
+ * @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.
+ */
+
+var defaultAttributes = {
+  xmlns: "http://www.w3.org/2000/svg",
+  width: 24,
+  height: 24,
+  viewBox: "0 0 24 24",
+  fill: "none",
+  stroke: "currentColor",
+  strokeWidth: 2,
+  strokeLinecap: "round",
+  strokeLinejoin: "round"
+};
+
+export { defaultAttributes as default };
+//# sourceMappingURL=defaultAttributes.mjs.map