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/play-off.mjs

@@ -0,0 +1,18 @@
+/**
+ * @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: "m10.215 4.56 9.79 5.71a2 2 0 0 1 .003 3.458l-.393.23", key: "fdtkwz" }],
+  ["path", { d: "m16.042 16.042-8.034 4.686A2 2 0 0 1 5 19V5", key: "1c8hxg" }],
+  ["path", { d: "m2 2 20 20", key: "1ooewy" }]
+];
+const PlayOff = createLucideIcon("play-off", __iconNode);
+
+export { __iconNode, PlayOff as default };
+//# sourceMappingURL=play-off.mjs.map