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/minimatch/dist/commonjs/escape.d.ts

@@ -0,0 +1,15 @@
+import type { MinimatchOptions } from './index.js';
+/**
+ * Escape all magic characters in a glob pattern.
+ *
+ * If the {@link MinimatchOptions.windowsPathsNoEscape}
+ * option is used, then characters are escaped by wrapping in `[]`, because
+ * a magic character wrapped in a character class can only be satisfied by
+ * that exact character.  In this mode, `\` is _not_ escaped, because it is
+ * not interpreted as a magic character, but instead as a path separator.
+ *
+ * If the {@link MinimatchOptions.magicalBraces} option is used,
+ * then braces (`{` and `}`) will be escaped.
+ */
+export declare const escape: (s: string, { windowsPathsNoEscape, magicalBraces, }?: Pick<MinimatchOptions, "windowsPathsNoEscape" | "magicalBraces">) => string;
+//# sourceMappingURL=escape.d.ts.map