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-module-transforms/lib/dynamic-import.js

@@ -0,0 +1,46 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.buildDynamicImport = buildDynamicImport;
+var _core = require("@babel/core");
+exports.getDynamicImportSource = function getDynamicImportSource(node) {
+  const [source] = node.arguments;
+  return _core.types.isStringLiteral(source) || _core.types.isTemplateLiteral(source) ? source : _core.template.expression.ast`\`\${${source}}\``;
+};
+function buildDynamicImport(node, deferToThen, wrapWithPromise, builder) {
+  const specifier = _core.types.isCallExpression(node) ? node.arguments[0] : node.source;
+  if (_core.types.isStringLiteral(specifier) || _core.types.isTemplateLiteral(specifier) && specifier.quasis.length === 0) {
+    if (deferToThen) {
+      return _core.template.expression.ast`
+        Promise.resolve().then(() => ${builder(specifier)})
+      `;
+    } else return builder(specifier);
+  }
+  const specifierToString = _core.types.isTemplateLiteral(specifier) ? _core.types.identifier("specifier") : _core.types.templateLiteral([_core.types.templateElement({
+    raw: ""
+  }), _core.types.templateElement({
+    raw: ""
+  })], [_core.types.identifier("specifier")]);
+  if (deferToThen) {
+    return _core.template.expression.ast`
+      (specifier =>
+        new Promise(r => r(${specifierToString}))
+          .then(s => ${builder(_core.types.identifier("s"))})
+      )(${specifier})
+    `;
+  } else if (wrapWithPromise) {
+    return _core.template.expression.ast`
+      (specifier =>
+        new Promise(r => r(${builder(specifierToString)}))
+      )(${specifier})
+    `;
+  } else {
+    return _core.template.expression.ast`
+      (specifier => ${builder(specifierToString)})(${specifier})
+    `;
+  }
+}
+
+//# sourceMappingURL=dynamic-import.js.map