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/heart-plus.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: "m14.479 19.374-.971.939a2 2 0 0 1-3 .019L5 15c-1.5-1.5-3-3.2-3-5.5a5.5 5.5 0 0 1 9.591-3.676.56.56 0 0 0 .818 0A5.49 5.49 0 0 1 22 9.5a5.2 5.2 0 0 1-.219 1.49",
+      key: "wg5jx"
+    }
+  ],
+  ["path", { d: "M15 15h6", key: "1u4692" }],
+  ["path", { d: "M18 12v6", key: "1houu1" }]
+];
+const HeartPlus = createLucideIcon("heart-plus", __iconNode);
+
+export { __iconNode, HeartPlus as default };
+//# sourceMappingURL=heart-plus.mjs.map