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/memory-stick.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 12v-2", key: "fwoke6" }],
+  ["path", { d: "M12 18v-2", key: "qj6yno" }],
+  ["path", { d: "M16 12v-2", key: "heuere" }],
+  ["path", { d: "M16 18v-2", key: "s1ct0w" }],
+  ["path", { d: "M2 11h1.5", key: "15p63e" }],
+  ["path", { d: "M20 18v-2", key: "12ehxp" }],
+  ["path", { d: "M20.5 11H22", key: "khsy7a" }],
+  ["path", { d: "M4 18v-2", key: "1c3oqr" }],
+  ["path", { d: "M8 12v-2", key: "1mwtfd" }],
+  ["path", { d: "M8 18v-2", key: "qcmpov" }],
+  ["rect", { x: "2", y: "6", width: "20", height: "10", rx: "2", key: "1qcswk" }]
+];
+const MemoryStick = createLucideIcon("memory-stick", __iconNode);
+
+export { __iconNode, MemoryStick as default };
+//# sourceMappingURL=memory-stick.mjs.map