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/save-plus.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: "M12.5 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h10.2a2 2 0 0 1 1.4.6l3.8 3.8a2 2 0 0 1 .6 1.4V12",
+      key: "bhibzn"
+    }
+  ],
+  ["path", { d: "M16 13H8a1 1 0 0 0-1 1v7", key: "164ge7" }],
+  ["path", { d: "M19 22v-6", key: "qhmiwi" }],
+  ["path", { d: "M22 19h-6", key: "vcuq98" }],
+  ["path", { d: "M7 3v4a1 1 0 0 0 1 1h7", key: "t51u73" }]
+];
+const SavePlus = createLucideIcon("save-plus", __iconNode);
+
+export { __iconNode, SavePlus as default };
+//# sourceMappingURL=save-plus.mjs.map