fix: raise provider HTTP timeouts from 30s to 10min

30-second resty client timeout was killing long streaming responses
mid-generation. Models with large output windows (e.g. deepseek-v4-pro
at 384K max_tokens) routinely exceed 30s. Raised all providers to
10 minutes (Ollama already at 15min, unchanged). Circuit breaker
recovery timeout raised from 30s to 5min.

internal/providers/circuit_breaker.go

@@ -17,7 +17,7 @@ func NewCircuitBreakerProvider(p Provider) Provider {
 	name := p.Name()
 	var maxRequests uint32 = 5
 	var interval = 60 * time.Second
-	var timeout = 30 * time.Second
+	var timeout = 5 * time.Minute
 
 	settings := gobreaker.Settings{
 		Name:        name,