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/bookmark-plus.mjs

@@ -0,0 +1,24 @@
+/**
+ * @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 7v6", key: "lw1j43" }],
+  ["path", { d: "M15 10H9", key: "o6yqo3" }],
+  [
+    "path",
+    {
+      d: "M17 3a2 2 0 0 1 2 2v15a1 1 0 0 1-1.496.868l-4.512-2.578a2 2 0 0 0-1.984 0l-4.512 2.578A1 1 0 0 1 5 20V5a2 2 0 0 1 2-2z",
+      key: "oz39mx"
+    }
+  ]
+];
+const BookmarkPlus = createLucideIcon("bookmark-plus", __iconNode);
+
+export { __iconNode, BookmarkPlus as default };
+//# sourceMappingURL=bookmark-plus.mjs.map