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/speech.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: "M8.8 20v-4.1l1.9.2a2.3 2.3 0 0 0 2.164-2.1V8.3A5.37 5.37 0 0 0 2 8.25c0 2.8.656 3.054 1 4.55a5.77 5.77 0 0 1 .029 2.758L2 20",
+      key: "11atix"
+    }
+  ],
+  ["path", { d: "M19.8 17.8a7.5 7.5 0 0 0 .003-10.603", key: "yol142" }],
+  ["path", { d: "M17 15a3.5 3.5 0 0 0-.025-4.975", key: "ssbmkc" }]
+];
+const Speech = createLucideIcon("speech", __iconNode);
+
+export { __iconNode, Speech as default };
+//# sourceMappingURL=speech.mjs.map