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/picture-in-picture.mjs

@@ -0,0 +1,20 @@
+/**
+ * @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: "M2 10h6V4", key: "zwrco" }],
+  ["path", { d: "m2 4 6 6", key: "ug085t" }],
+  ["path", { d: "M21 10V7a2 2 0 0 0-2-2h-7", key: "git5jr" }],
+  ["path", { d: "M3 14v2a2 2 0 0 0 2 2h3", key: "1f7fh3" }],
+  ["rect", { x: "12", y: "14", width: "10", height: "7", rx: "1", key: "1wjs3o" }]
+];
+const PictureInPicture = createLucideIcon("picture-in-picture", __iconNode);
+
+export { __iconNode, PictureInPicture as default };
+//# sourceMappingURL=picture-in-picture.mjs.map