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/plugin-bugfix-safari-rest-destructuring-rhs-array/lib/util.js

@@ -0,0 +1,32 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.isPathSimpleArrayWithLength = isPathSimpleArrayWithLength;
+exports.shouldTransform = shouldTransform;
+var _helperSkipTransparentExpressionWrappers = require("@babel/helper-skip-transparent-expression-wrappers");
+function isPathSimpleArrayWithLength(path, N) {
+  var _path$node$extra;
+  if (!path.isArrayExpression()) {
+    return false;
+  }
+  const elementPaths = path.get("elements");
+  return elementPaths.length === N && elementPaths.every(elementPath => elementPath.node && !elementPath.isSpreadElement()) && !((_path$node$extra = path.node.extra) != null && _path$node$extra.trailingComma);
+}
+function shouldTransform(path) {
+  const elementPaths = path.get("elements");
+  const elementPathsLength = elementPaths.length;
+  if (elementPaths[elementPathsLength - 1].isRestElement()) {
+    const {
+      parentPath
+    } = path;
+    const rhsPath = parentPath.isVariableDeclarator() ? parentPath.get("init") : parentPath.isAssignmentExpression() ? parentPath.get("right") : null;
+    if (rhsPath != null && rhsPath.node && isPathSimpleArrayWithLength((0, _helperSkipTransparentExpressionWrappers.skipTransparentExprWrappers)(rhsPath), elementPathsLength)) {
+      return rhsPath;
+    }
+  }
+  return false;
+}
+
+//# sourceMappingURL=util.js.map