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/triangle-dashed.mjs

@@ -0,0 +1,24 @@
+/**
+ * @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: "M10.17 4.193a2 2 0 0 1 3.666.013", key: "pltmmw" }],
+  ["path", { d: "M14 21h2", key: "v4qezv" }],
+  ["path", { d: "m15.874 7.743 1 1.732", key: "10m0iw" }],
+  ["path", { d: "m18.849 12.952 1 1.732", key: "zadnam" }],
+  ["path", { d: "M21.824 18.18a2 2 0 0 1-1.835 2.824", key: "fvwuk4" }],
+  ["path", { d: "M4.024 21a2 2 0 0 1-1.839-2.839", key: "1e1kah" }],
+  ["path", { d: "m5.136 12.952-1 1.732", key: "1u4ldi" }],
+  ["path", { d: "M8 21h2", key: "i9zjee" }],
+  ["path", { d: "m8.102 7.743-1 1.732", key: "1zzo4u" }]
+];
+const TriangleDashed = createLucideIcon("triangle-dashed", __iconNode);
+
+export { __iconNode, TriangleDashed as default };
+//# sourceMappingURL=triangle-dashed.mjs.map