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-syntax-import-assertions/lib/index.js

@@ -0,0 +1,32 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = void 0;
+var _helperPluginUtils = require("@babel/helper-plugin-utils");
+var _default = exports.default = (0, _helperPluginUtils.declare)(api => {
+  api.assertVersion("^7.0.0-0 || ^8.0.0-0");
+  const isPlugin = (plugin, name) => name === "plugin" || Array.isArray(plugin) && plugin[0] === "plugin";
+  const options = plugin => Array.isArray(plugin) && plugin.length > 1 ? plugin[1] : {};
+  return {
+    name: "syntax-import-assertions",
+    manipulateOptions(opts, {
+      plugins
+    }) {
+      for (let i = 0; i < plugins.length; i++) {
+        const plugin = plugins[i];
+        if (isPlugin(plugin, "deprecatedImportAssert")) return;
+        if (isPlugin(plugin, "importAttributes")) {
+          plugins.splice(i, 1, "deprecatedImportAssert", ["importAttributes", Object.assign({}, options(plugin), {
+            deprecatedAssertSyntax: true
+          })]);
+          return;
+        }
+      }
+      plugins.push("importAssertions");
+    }
+  };
+});
+
+//# sourceMappingURL=index.js.map