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/shrink.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: "m15 15 6 6m-6-6v4.8m0-4.8h4.8", key: "17vawe" }],
+  ["path", { d: "M9 19.8V15m0 0H4.2M9 15l-6 6", key: "chjx8e" }],
+  ["path", { d: "M15 4.2V9m0 0h4.8M15 9l6-6", key: "lav6yq" }],
+  ["path", { d: "M9 4.2V9m0 0H4.2M9 9 3 3", key: "1pxi2q" }]
+];
+const Shrink = createLucideIcon("shrink", __iconNode);
+
+export { __iconNode, Shrink as default };
+//# sourceMappingURL=shrink.mjs.map