feat(agent): agent stream tunneling with TLS and dTLS (UDP); combined agent APIs

- Add `StreamPort` configuration to agent configuration and environment variables
- Implement TCP and UDP stream client support in agent package
- Update agent verification to test stream connectivity (TCP/UDP)
- Add `/info` endpoint to agent HTTP handler for version, name, runtime, and stream port
- Remove /version, /name, /runtime APIs, replaced by /info
- Update agent compose template to expose stream port for TCP and UDP
- Update agent creation API to optionally specify stream port (defaults to port + 1)
- Modify `StreamRoute` to pass agent configuration to stream implementations
- Update `TCPTCPStream` and `UDPUDPStream` to use agent stream tunneling when agent is configured
- Add support for both direct connections and agent-tunneled connections in stream routes

This enables agents to handle TCP and UDP route tunneling, expanding the proxy capabilities beyond HTTP-only connections.

agent/pkg/env/env.go

@@ -20,6 +20,7 @@ func DefaultAgentName() string {
 var (
 	AgentName                string
 	AgentPort                int
+	AgentStreamPort          int
 	AgentSkipClientCertCheck bool
 	AgentCACert              string
 	AgentSSLCert             string
@@ -35,6 +36,7 @@ func Load() {
 	DockerSocket = env.GetEnvString("DOCKER_SOCKET", "/var/run/docker.sock")
 	AgentName = env.GetEnvString("AGENT_NAME", DefaultAgentName())
 	AgentPort = env.GetEnvInt("AGENT_PORT", 8890)
+	AgentStreamPort = env.GetEnvInt("AGENT_STREAM_PORT", AgentPort+1)
 	AgentSkipClientCertCheck = env.GetEnvBool("AGENT_SKIP_CLIENT_CERT_CHECK", false)
 
 	AgentCACert = env.GetEnvString("AGENT_CA_CERT", "")