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/sun-medium.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 = [
+  ["circle", { cx: "12", cy: "12", r: "4", key: "4exip2" }],
+  ["path", { d: "M12 3v1", key: "1asbbs" }],
+  ["path", { d: "M12 20v1", key: "1wcdkc" }],
+  ["path", { d: "M3 12h1", key: "lp3yf2" }],
+  ["path", { d: "M20 12h1", key: "1vloll" }],
+  ["path", { d: "m18.364 5.636-.707.707", key: "1hakh0" }],
+  ["path", { d: "m6.343 17.657-.707.707", key: "18m9nf" }],
+  ["path", { d: "m5.636 5.636.707.707", key: "1xv1c5" }],
+  ["path", { d: "m17.657 17.657.707.707", key: "vl76zb" }]
+];
+const SunMedium = createLucideIcon("sun-medium", __iconNode);
+
+export { __iconNode, SunMedium as default };
+//# sourceMappingURL=sun-medium.mjs.map