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/unlink.mjs

@@ -0,0 +1,33 @@
+/**
+ * @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: "m18.84 12.25 1.72-1.71h-.02a5.004 5.004 0 0 0-.12-7.07 5.006 5.006 0 0 0-6.95 0l-1.72 1.71",
+      key: "yqzxt4"
+    }
+  ],
+  [
+    "path",
+    {
+      d: "m5.17 11.75-1.71 1.71a5.004 5.004 0 0 0 .12 7.07 5.006 5.006 0 0 0 6.95 0l1.71-1.71",
+      key: "4qinb0"
+    }
+  ],
+  ["line", { x1: "8", x2: "8", y1: "2", y2: "5", key: "1041cp" }],
+  ["line", { x1: "2", x2: "5", y1: "8", y2: "8", key: "14m1p5" }],
+  ["line", { x1: "16", x2: "16", y1: "19", y2: "22", key: "rzdirn" }],
+  ["line", { x1: "19", x2: "22", y1: "16", y2: "16", key: "ox905f" }]
+];
+const Unlink = createLucideIcon("unlink", __iconNode);
+
+export { __iconNode, Unlink as default };
+//# sourceMappingURL=unlink.mjs.map