Retrieves the current available credit limit for a customer in real-time.

• available_limit: net credit available — total_granted_limit minus committed_amount, floored at zero. This is how much the customer can still borrow.
• committed_amount: outstanding principal across all APPROVED and FUNDED applications, net of payments and refunds already received.
• total_granted_limit: the credit limit approved by the credit engine (before deductions). Same as max_total_value returned by the create endpoint.