- 4 tasks: failing test, helper implementation, vaultLoop switch, smoke check
- New helper fetchLiveVaultBalance(string $user): ?int in includes/utilities.php
- vaultLoop prefers the live value, falls back to MAX(running_balance)
- Per-request cache to avoid N HTTP calls
- Test hook via $GLOBALS['liveBalanceTestHook'] for unit testing
- Falls back gracefully on API failure
