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/lamp-wall-up.mjs

@@ -0,0 +1,27 @@
+/**
+ * @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: "M19.929 9.629A1 1 0 0 1 19 11H9a1 1 0 0 1-.928-1.371l2-5A1 1 0 0 1 11 4h6a1 1 0 0 1 .928.629z",
+      key: "1uvrbf"
+    }
+  ],
+  [
+    "path",
+    { d: "M6 15a2 2 0 0 1 2 2v2a2 2 0 0 1-2 2H5a1 1 0 0 1-1-1v-4a1 1 0 0 1 1-1z", key: "154r2a" }
+  ],
+  ["path", { d: "M8 18h4a2 2 0 0 0 2-2v-5", key: "z9mbu0" }]
+];
+const LampWallUp = createLucideIcon("lamp-wall-up", __iconNode);
+
+export { __iconNode, LampWallUp as default };
+//# sourceMappingURL=lamp-wall-up.mjs.map