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/puzzle.mjs

@@ -0,0 +1,22 @@
+/**
+ * @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: "M15.39 4.39a1 1 0 0 0 1.68-.474 2.5 2.5 0 1 1 3.014 3.015 1 1 0 0 0-.474 1.68l1.683 1.682a2.414 2.414 0 0 1 0 3.414L19.61 15.39a1 1 0 0 1-1.68-.474 2.5 2.5 0 1 0-3.014 3.015 1 1 0 0 1 .474 1.68l-1.683 1.682a2.414 2.414 0 0 1-3.414 0L8.61 19.61a1 1 0 0 0-1.68.474 2.5 2.5 0 1 1-3.014-3.015 1 1 0 0 0 .474-1.68l-1.683-1.682a2.414 2.414 0 0 1 0-3.414L4.39 8.61a1 1 0 0 1 1.68.474 2.5 2.5 0 1 0 3.014-3.015 1 1 0 0 1-.474-1.68l1.683-1.682a2.414 2.414 0 0 1 3.414 0z",
+      key: "w46dr5"
+    }
+  ]
+];
+const Puzzle = createLucideIcon("puzzle", __iconNode);
+
+export { __iconNode, Puzzle as default };
+//# sourceMappingURL=puzzle.mjs.map