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/folder-key.mjs

@@ -0,0 +1,25 @@
+/**
+ * @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: "M13 20H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h3.9a2 2 0 0 1 1.69.9l.81 1.2a2 2 0 0 0 1.67.9H20a2 2 0 0 1 2 2v1.36",
+      key: "1shsnm"
+    }
+  ],
+  ["path", { d: "M19 12v6", key: "kflna4" }],
+  ["path", { d: "M19 14h2", key: "wp2qbk" }],
+  ["circle", { cx: "19", cy: "20", r: "2", key: "1jfyz6" }]
+];
+const FolderKey = createLucideIcon("folder-key", __iconNode);
+
+export { __iconNode, FolderKey as default };
+//# sourceMappingURL=folder-key.mjs.map