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/image-minus.mjs

@@ -0,0 +1,19 @@
+/**
+ * @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 9v10a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h7", key: "m87ecr" }],
+  ["line", { x1: "16", x2: "22", y1: "5", y2: "5", key: "ez7e4s" }],
+  ["circle", { cx: "9", cy: "9", r: "2", key: "af1f0g" }],
+  ["path", { d: "m21 15-3.086-3.086a2 2 0 0 0-2.828 0L6 21", key: "1xmnt7" }]
+];
+const ImageMinus = createLucideIcon("image-minus", __iconNode);
+
+export { __iconNode, ImageMinus as default };
+//# sourceMappingURL=image-minus.mjs.map