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/git-merge-conflict.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: "M12 6h4a2 2 0 0 1 2 2v7", key: "18ej7s" }],
+  ["path", { d: "M6 12v9", key: "9e33v1" }],
+  ["path", { d: "M9 3 3 9", key: "ahyygn" }],
+  ["path", { d: "M9 9 3 3", key: "v551iv" }],
+  ["circle", { cx: "18", cy: "18", r: "3", key: "1xkwt0" }]
+];
+const GitMergeConflict = createLucideIcon("git-merge-conflict", __iconNode);
+
+export { __iconNode, GitMergeConflict as default };
+//# sourceMappingURL=git-merge-conflict.mjs.map