HttpTransportFactory

Factory for managing HttpTransport instances.

This factory provides:

• A lazily-initialized default HttpTransport singleton

• Registration of custom HttpTransport instances for lifecycle management

• Automatic cleanup via JVM shutdown hook

Usage examples:

`// Get the default transport (lazily created)
HttpTransport transport = HttpTransportFactory.getDefault();

// Set a custom default transport
HttpTransport custom = OkHttpTransport.builder()
.config(HttpTransportConfig.builder()
.connectTimeout(Duration.ofSeconds(30))
.build())
.build();
HttpTransportFactory.setDefault(custom);

// Register a transport for automatic cleanup
HttpTransportFactory.register(myTransport);
`

All registered transports and the default transport will be closed during JVM shutdown, orchestrated by AgentScopeJvmShutdownHook after all agents have finished processing.