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/heart-x.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: "m15.5 12.5 5 5", key: "15wbfr" }],
+  ["path", { d: "m20.5 12.5-5 5", key: "o012pn" }],
+  [
+    "path",
+    {
+      d: "M21.955 8.774a5.5 5.5 0 0 0-9.546-2.95.6.6 0 0 1-.818 0A5.5 5.5 0 0 0 2 9.5c0 2.3 1.5 4 3 5.5l5.508 5.332a2 2 0 0 0 2.57.352",
+      key: "c1obtn"
+    }
+  ]
+];
+const HeartX = createLucideIcon("heart-x", __iconNode);
+
+export { __iconNode, HeartX as default };
+//# sourceMappingURL=heart-x.mjs.map