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/decimals-arrow-right.mjs

@@ -0,0 +1,20 @@
+/**
+ * @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: "M10 18h10", key: "1y5s8o" }],
+  ["path", { d: "m17 21 3-3-3-3", key: "1ammt0" }],
+  ["path", { d: "M3 11h.01", key: "1eifu7" }],
+  ["rect", { x: "15", y: "3", width: "5", height: "8", rx: "2.5", key: "76md6a" }],
+  ["rect", { x: "6", y: "3", width: "5", height: "8", rx: "2.5", key: "v9paqo" }]
+];
+const DecimalsArrowRight = createLucideIcon("decimals-arrow-right", __iconNode);
+
+export { __iconNode, DecimalsArrowRight as default };
+//# sourceMappingURL=decimals-arrow-right.mjs.map