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/@babel/helper-compilation-targets/lib/options.js

@@ -0,0 +1,24 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.TargetNames = void 0;
+const TargetNames = exports.TargetNames = {
+  node: "node",
+  deno: "deno",
+  chrome: "chrome",
+  opera: "opera",
+  edge: "edge",
+  firefox: "firefox",
+  safari: "safari",
+  ie: "ie",
+  ios: "ios",
+  android: "android",
+  electron: "electron",
+  samsung: "samsung",
+  rhino: "rhino",
+  opera_mobile: "opera_mobile"
+};
+
+//# sourceMappingURL=options.js.map