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/house-plug.mjs

@@ -0,0 +1,28 @@
+/**
+ * @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 12V8.964", key: "1vll13" }],
+  ["path", { d: "M14 12V8.964", key: "1x3qvg" }],
+  [
+    "path",
+    { d: "M15 12a1 1 0 0 1 1 1v2a2 2 0 0 1-2 2h-4a2 2 0 0 1-2-2v-2a1 1 0 0 1 1-1z", key: "ppykja" }
+  ],
+  [
+    "path",
+    {
+      d: "M8.5 21H5a2 2 0 0 1-2-2v-9a2 2 0 0 1 .709-1.528l7-6a2 2 0 0 1 2.582 0l7 6A2 2 0 0 1 21 10v9a2 2 0 0 1-2 2h-5a2 2 0 0 1-2-2v-2",
+      key: "365xoy"
+    }
+  ]
+];
+const HousePlug = createLucideIcon("house-plug", __iconNode);
+
+export { __iconNode, HousePlug as default };
+//# sourceMappingURL=house-plug.mjs.map