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/traverse/lib/path/inference/util.js

@@ -0,0 +1,28 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.createUnionType = createUnionType;
+var _t = require("@babel/types");
+const {
+  createFlowUnionType,
+  createTSUnionType,
+  createUnionTypeAnnotation,
+  isFlowType,
+  isTSType
+} = _t;
+function createUnionType(types) {
+  if (types.every(v => isFlowType(v))) {
+    if (createFlowUnionType) {
+      return createFlowUnionType(types);
+    }
+    return createUnionTypeAnnotation(types);
+  } else if (types.every(v => isTSType(v))) {
+    if (createTSUnionType) {
+      return createTSUnionType(types);
+    }
+  }
+}
+
+//# sourceMappingURL=util.js.map