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/spray-can.mjs

@@ -0,0 +1,25 @@
+/**
+ * @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: "M3 3h.01", key: "159qn6" }],
+  ["path", { d: "M7 5h.01", key: "1hq22a" }],
+  ["path", { d: "M11 7h.01", key: "1osv80" }],
+  ["path", { d: "M3 7h.01", key: "1xzrh3" }],
+  ["path", { d: "M7 9h.01", key: "19b3jx" }],
+  ["path", { d: "M3 11h.01", key: "1eifu7" }],
+  ["rect", { width: "4", height: "4", x: "15", y: "5", key: "mri9e4" }],
+  ["path", { d: "m19 9 2 2v10c0 .6-.4 1-1 1h-6c-.6 0-1-.4-1-1V11l2-2", key: "aib6hk" }],
+  ["path", { d: "m13 14 8-2", key: "1d7bmk" }],
+  ["path", { d: "m13 19 8-2", key: "1y2vml" }]
+];
+const SprayCan = createLucideIcon("spray-can", __iconNode);
+
+export { __iconNode, SprayCan as default };
+//# sourceMappingURL=spray-can.mjs.map