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/unplug.mjs

@@ -0,0 +1,27 @@
+/**
+ * @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: "m19 5 3-3", key: "yk6iyv" }],
+  ["path", { d: "m2 22 3-3", key: "19mgm9" }],
+  [
+    "path",
+    { d: "M6.3 20.3a2.4 2.4 0 0 0 3.4 0L12 18l-6-6-2.3 2.3a2.4 2.4 0 0 0 0 3.4Z", key: "goz73y" }
+  ],
+  ["path", { d: "M7.5 13.5 10 11", key: "7xgeeb" }],
+  ["path", { d: "M10.5 16.5 13 14", key: "10btkg" }],
+  [
+    "path",
+    { d: "m12 6 6 6 2.3-2.3a2.4 2.4 0 0 0 0-3.4l-2.6-2.6a2.4 2.4 0 0 0-3.4 0Z", key: "1snsnr" }
+  ]
+];
+const Unplug = createLucideIcon("unplug", __iconNode);
+
+export { __iconNode, Unplug as default };
+//# sourceMappingURL=unplug.mjs.map