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/circuit-board.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 = [
+  ["rect", { width: "18", height: "18", x: "3", y: "3", rx: "2", key: "afitv7" }],
+  ["path", { d: "M11 9h4a2 2 0 0 0 2-2V3", key: "1ve2rv" }],
+  ["circle", { cx: "9", cy: "9", r: "2", key: "af1f0g" }],
+  ["path", { d: "M7 21v-4a2 2 0 0 1 2-2h4", key: "1fwkro" }],
+  ["circle", { cx: "15", cy: "15", r: "2", key: "3i40o0" }]
+];
+const CircuitBoard = createLucideIcon("circuit-board", __iconNode);
+
+export { __iconNode, CircuitBoard as default };
+//# sourceMappingURL=circuit-board.mjs.map