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/webhook.mjs

@@ -0,0 +1,24 @@
+/**
+ * @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 16.98h-5.99c-1.1 0-1.95.94-2.48 1.9A4 4 0 0 1 2 17c.01-.7.2-1.4.57-2",
+      key: "q3hayz"
+    }
+  ],
+  ["path", { d: "m6 17 3.13-5.78c.53-.97.1-2.18-.5-3.1a4 4 0 1 1 6.89-4.06", key: "1go1hn" }],
+  ["path", { d: "m12 6 3.13 5.73C15.66 12.7 16.9 13 18 13a4 4 0 0 1 0 8", key: "qlwsc0" }]
+];
+const Webhook = createLucideIcon("webhook", __iconNode);
+
+export { __iconNode, Webhook as default };
+//# sourceMappingURL=webhook.mjs.map