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/brain.mjs

@@ -0,0 +1,23 @@
+/**
+ * @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 18V5", key: "adv99a" }],
+  ["path", { d: "M15 13a4.17 4.17 0 0 1-3-4 4.17 4.17 0 0 1-3 4", key: "1e3is1" }],
+  ["path", { d: "M17.598 6.5A3 3 0 1 0 12 5a3 3 0 1 0-5.598 1.5", key: "1gqd8o" }],
+  ["path", { d: "M17.997 5.125a4 4 0 0 1 2.526 5.77", key: "iwvgf7" }],
+  ["path", { d: "M18 18a4 4 0 0 0 2-7.464", key: "efp6ie" }],
+  ["path", { d: "M19.967 17.483A4 4 0 1 1 12 18a4 4 0 1 1-7.967-.517", key: "1gq6am" }],
+  ["path", { d: "M6 18a4 4 0 0 1-2-7.464", key: "k1g0md" }],
+  ["path", { d: "M6.003 5.125a4 4 0 0 0-2.526 5.77", key: "q97ue3" }]
+];
+const Brain = createLucideIcon("brain", __iconNode);
+
+export { __iconNode, Brain as default };
+//# sourceMappingURL=brain.mjs.map