Function record_circuit_breaker_outcome 

pub fn record_circuit_breaker_outcome(endpoint_pattern: &str, success: bool)

What: Record request outcome in circuit breaker.

Inputs:

• endpoint_pattern: Endpoint pattern for this request
• success: true if request succeeded, false if it failed

Output: None

Details:

• Records outcome in recent history (max 10 entries).
• On success: resets failure count, moves to Closed.
• On failure: increments failure count, opens circuit if >50% failure rate.