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/graduation-cap.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: "M21.42 10.922a1 1 0 0 0-.019-1.838L12.83 5.18a2 2 0 0 0-1.66 0L2.6 9.08a1 1 0 0 0 0 1.832l8.57 3.908a2 2 0 0 0 1.66 0z",
+      key: "j76jl0"
+    }
+  ],
+  ["path", { d: "M22 10v6", key: "1lu8f3" }],
+  ["path", { d: "M6 12.5V16a6 3 0 0 0 12 0v-3.5", key: "1r8lef" }]
+];
+const GraduationCap = createLucideIcon("graduation-cap", __iconNode);
+
+export { __iconNode, GraduationCap as default };
+//# sourceMappingURL=graduation-cap.mjs.map