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/bottle-wine.mjs

@@ -0,0 +1,23 @@
+/**
+ * @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: "M10 3a1 1 0 0 1 1-1h2a1 1 0 0 1 1 1v2a6 6 0 0 0 1.2 3.6l.6.8A6 6 0 0 1 17 13v8a1 1 0 0 1-1 1H8a1 1 0 0 1-1-1v-8a6 6 0 0 1 1.2-3.6l.6-.8A6 6 0 0 0 10 5z",
+      key: "blqgoc"
+    }
+  ],
+  ["path", { d: "M17 13h-4a1 1 0 0 0-1 1v3a1 1 0 0 0 1 1h4", key: "43jbee" }]
+];
+const BottleWine = createLucideIcon("bottle-wine", __iconNode);
+
+export { __iconNode, BottleWine as default };
+//# sourceMappingURL=bottle-wine.mjs.map