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/cloud-sun-rain.mjs

@@ -0,0 +1,23 @@
+/**
+ * @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: "M12 2v2", key: "tus03m" }],
+  ["path", { d: "m4.93 4.93 1.41 1.41", key: "149t6j" }],
+  ["path", { d: "M20 12h2", key: "1q8mjw" }],
+  ["path", { d: "m19.07 4.93-1.41 1.41", key: "1shlcs" }],
+  ["path", { d: "M15.947 12.65a4 4 0 0 0-5.925-4.128", key: "dpwdj0" }],
+  ["path", { d: "M3 20a5 5 0 1 1 8.9-4H13a3 3 0 0 1 2 5.24", key: "1qmrp3" }],
+  ["path", { d: "M11 20v2", key: "174qtz" }],
+  ["path", { d: "M7 19v2", key: "12npes" }]
+];
+const CloudSunRain = createLucideIcon("cloud-sun-rain", __iconNode);
+
+export { __iconNode, CloudSunRain as default };
+//# sourceMappingURL=cloud-sun-rain.mjs.map