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/umbrella-off.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: "M12 13v7a2 2 0 0 0 4 0", key: "rpgb42" }],
+  ["path", { d: "M12 2v2", key: "tus03m" }],
+  [
+    "path",
+    { d: "M18.656 13h2.336a1 1 0 0 0 .97-1.274 10.284 10.284 0 0 0-12.07-7.51", key: "yawknk" }
+  ],
+  ["path", { d: "m2 2 20 20", key: "1ooewy" }],
+  ["path", { d: "M5.961 5.957a10.28 10.28 0 0 0-3.922 5.769A1 1 0 0 0 3 13h10", key: "5sfalc" }]
+];
+const UmbrellaOff = createLucideIcon("umbrella-off", __iconNode);
+
+export { __iconNode, UmbrellaOff as default };
+//# sourceMappingURL=umbrella-off.mjs.map