List open and pending orders for an account

Returns orders in PENDING/PARTIALLY_FILLED/ACCEPTED/QUEUED/TRIGGERED status. Executed orders surface through the /trades endpoint instead. Returns an empty list for providers that do not expose orders (Plaid, SaltEdge). Responses may be served from a cache up to 6 hours old: X-BankSync-Cache says hit, miss or bypass, and Age is the cached answer's age in seconds.