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/preset-env/lib/debug.js

@@ -0,0 +1,35 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.logPlugin = void 0;
+var _helperCompilationTargets = require("@babel/helper-compilation-targets");
+const compatData = require("@babel/compat-data/plugins");
+const logPlugin = (item, targetVersions, list) => {
+  const filteredList = (0, _helperCompilationTargets.getInclusionReasons)(item, targetVersions, list);
+  const support = list[item];
+  if (item.startsWith("transform-")) {
+    const proposalName = `proposal-${item.slice(10)}`;
+    if (proposalName === "proposal-dynamic-import" || hasOwnProperty.call(compatData, proposalName)) {
+      item = proposalName;
+    }
+  }
+  if (!support) {
+    console.log(`  ${item}`);
+    return;
+  }
+  let formattedTargets = `{`;
+  let first = true;
+  for (const target of Object.keys(filteredList)) {
+    if (!first) formattedTargets += `,`;
+    first = false;
+    formattedTargets += ` ${target}`;
+    if (support[target]) formattedTargets += ` < ${support[target]}`;
+  }
+  formattedTargets += ` }`;
+  console.log(`  ${item} ${formattedTargets}`);
+};
+exports.logPlugin = logPlugin;
+
+//# sourceMappingURL=debug.js.map