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/lucide-react/dist/esm/context.mjs

@@ -0,0 +1,36 @@
+"use strict";
+"use client";
+/**
+ * @license lucide-react v1.24.0 - ISC
+ *
+ * This source code is licensed under the ISC license.
+ * See the LICENSE file in the root directory of this source tree.
+ */
+
+import { createContext, useContext, useMemo, createElement } from 'react';
+
+const LucideContext = createContext({});
+function LucideProvider({
+  children,
+  size,
+  color,
+  strokeWidth,
+  absoluteStrokeWidth,
+  className
+}) {
+  const value = useMemo(
+    () => ({
+      size,
+      color,
+      strokeWidth,
+      absoluteStrokeWidth,
+      className
+    }),
+    [size, color, strokeWidth, absoluteStrokeWidth, className]
+  );
+  return createElement(LucideContext.Provider, { value }, children);
+}
+const useLucideContext = () => useContext(LucideContext);
+
+export { LucideProvider, useLucideContext };
+//# sourceMappingURL=context.mjs.map