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/squircle-dashed.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: "M13.77 3.043a34 34 0 0 0-3.54 0", key: "1oaobr" }],
+  ["path", { d: "M13.771 20.956a33 33 0 0 1-3.541.001", key: "95iq0j" }],
+  ["path", { d: "M20.18 17.74c-.51 1.15-1.29 1.93-2.439 2.44", key: "1u6qty" }],
+  ["path", { d: "M20.18 6.259c-.51-1.148-1.291-1.929-2.44-2.438", key: "1ew6g6" }],
+  ["path", { d: "M20.957 10.23a33 33 0 0 1 0 3.54", key: "1l9npr" }],
+  ["path", { d: "M3.043 10.23a34 34 0 0 0 .001 3.541", key: "1it6jm" }],
+  ["path", { d: "M6.26 20.179c-1.15-.508-1.93-1.29-2.44-2.438", key: "14uchd" }],
+  ["path", { d: "M6.26 3.82c-1.149.51-1.93 1.291-2.44 2.44", key: "8k4agb" }]
+];
+const SquircleDashed = createLucideIcon("squircle-dashed", __iconNode);
+
+export { __iconNode, SquircleDashed as default };
+//# sourceMappingURL=squircle-dashed.mjs.map