registerUser() declared `: string|true`; the bare `true` type requires
PHP 8.2, so including auth.php was a fatal error on PHP 8.0/8.1 — every
login/API call returned 500 while install.php (which doesn't include
auth.php) worked. Use string|bool instead. Also install a JSON exception
handler so future server errors surface a message to the SPA instead of
a blank 500.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Harwinder Sekhon
aba6ef4734