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-commit-horizontal.mjs

@@ -0,0 +1,18 @@
+/**
+ * @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 = [
+  ["circle", { cx: "12", cy: "12", r: "3", key: "1v7zrd" }],
+  ["line", { x1: "3", x2: "9", y1: "12", y2: "12", key: "1dyftd" }],
+  ["line", { x1: "15", x2: "21", y1: "12", y2: "12", key: "oup4p8" }]
+];
+const GitCommitHorizontal = createLucideIcon("git-commit-horizontal", __iconNode);
+
+export { __iconNode, GitCommitHorizontal as default };
+//# sourceMappingURL=git-commit-horizontal.mjs.map