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/images.mjs

@@ -0,0 +1,19 @@
+/**
+ * @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: "m22 11-1.296-1.296a2.4 2.4 0 0 0-3.408 0L11 16", key: "9kzy35" }],
+  ["path", { d: "M4 8a2 2 0 0 0-2 2v10a2 2 0 0 0 2 2h10a2 2 0 0 0 2-2", key: "1t0f0t" }],
+  ["circle", { cx: "13", cy: "7", r: "1", fill: "currentColor", key: "1obus6" }],
+  ["rect", { x: "8", y: "2", width: "14", height: "14", rx: "2", key: "1gvhby" }]
+];
+const Images = createLucideIcon("images", __iconNode);
+
+export { __iconNode, Images as default };
+//# sourceMappingURL=images.mjs.map