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/earth-lock.mjs

@@ -0,0 +1,21 @@
+/**
+ * @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: "M7 3.34V5a3 3 0 0 0 3 3", key: "w732o8" }],
+  ["path", { d: "M11 21.95V18a2 2 0 0 0-2-2 2 2 0 0 1-2-2v-1a2 2 0 0 0-2-2H2.05", key: "f02343" }],
+  ["path", { d: "M21.54 15H17a2 2 0 0 0-2 2v4.54", key: "1djwo0" }],
+  ["path", { d: "M12 2a10 10 0 1 0 9.54 13", key: "zjsr6q" }],
+  ["path", { d: "M20 6V4a2 2 0 1 0-4 0v2", key: "1of5e8" }],
+  ["rect", { width: "8", height: "5", x: "14", y: "6", rx: "1", key: "1fmf51" }]
+];
+const EarthLock = createLucideIcon("earth-lock", __iconNode);
+
+export { __iconNode, EarthLock as default };
+//# sourceMappingURL=earth-lock.mjs.map