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/megaphone.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: "M11 6a13 13 0 0 0 8.4-2.8A1 1 0 0 1 21 4v12a1 1 0 0 1-1.6.8A13 13 0 0 0 11 14H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2z",
+      key: "q8bfy3"
+    }
+  ],
+  ["path", { d: "M6 14a12 12 0 0 0 2.4 7.2 2 2 0 0 0 3.2-2.4A8 8 0 0 1 10 14", key: "1853fq" }],
+  ["path", { d: "M8 6v8", key: "15ugcq" }]
+];
+const Megaphone = createLucideIcon("megaphone", __iconNode);
+
+export { __iconNode, Megaphone as default };
+//# sourceMappingURL=megaphone.mjs.map