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/chess-queen.mjs

@@ -0,0 +1,26 @@
+/**
+ * @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: "M4 20a2 2 0 0 1 2-2h12a2 2 0 0 1 2 2v1a1 1 0 0 1-1 1H5a1 1 0 0 1-1-1z", key: "mqzwx6" }
+  ],
+  ["path", { d: "m12.474 5.943 1.567 5.34a1 1 0 0 0 1.75.328l2.616-3.402", key: "1js4gl" }],
+  ["path", { d: "m20 9-3 9", key: "r75r3f" }],
+  ["path", { d: "m5.594 8.209 2.615 3.403a1 1 0 0 0 1.75-.329l1.567-5.34", key: "1joj19" }],
+  ["path", { d: "M7 18 4 9", key: "1mfzj8" }],
+  ["circle", { cx: "12", cy: "4", r: "2", key: "muu5ef" }],
+  ["circle", { cx: "20", cy: "7", r: "2", key: "9w7p1x" }],
+  ["circle", { cx: "4", cy: "7", r: "2", key: "1d9wy8" }]
+];
+const ChessQueen = createLucideIcon("chess-queen", __iconNode);
+
+export { __iconNode, ChessQueen as default };
+//# sourceMappingURL=chess-queen.mjs.map